Lopez has been influenced by artists such as Tina Turner, James Brown, Michael Jackson, Madonna and Barbra Streisand. She credited Rita Moreno's performance in the 1961 musical film West Side Story as a major inspiration. Critics have considered Lopez's voice to be limited, and obscured by the production of her music, while remaining "radio-friendly". Rob Sheffield of Rolling Stone observed: "Instead of strained vocal pyrotechnics, Lopez sticks to the understated R&B murmur of a round-the-way superstar who doesn't need to belt because she knows you're already paying attention [...] She makes a little va-va and a whole lot of voom go a long way." Meanwhile, AllMusic's Stephen Thomas Erlewine called her voice "slight" and wrote: "Lopez was never, ever about singing; she was about style". Entertainment Weekly criticized her vocal performance for lacking the trademark "husky-voiced voluptuousness" she has in her films. J. D. Considine of The Baltimore Sun regards Lopez as having a "breathy" stylistic range, but lacking personality.

Jennifer Lynn Lopez was born on July 24, 1969, in The Bronx borough of New York City, to Puerto Rican parents Guadalupe Rodríguez and David López. She has an older sister, Leslie, and a younger sister, Lynda, a Journalist. David worked the night shift at the Guardian Insurance Company before becoming a computer technician at the firm, while Guadalupe was a homemaker. When Lopez was born, the family was living in a small apartment in the Castle Hill neighborhood. A few years later, her parents had saved up enough money to be able to purchase a two-story house, which was considered a big deal for the relatively poor family. At the age of five, Lopez began taking singing and dancing lessons. She toured New York with her school when she was seven years old. Her parents stressed the importance of work ethic and being able to speak English. They encouraged their three daughters to put on performances at home—singing and dancing in front of each other and their friends so that they would stay "out of trouble". Lopez spent her entire academic career in Catholic schools, finishing at Preston High School. In school, Lopez did gymnastics, ran track on a national level, and was a member of the school's softball team. She excelled athletically rather than academically, competing in national track championships.

While attending her final year of high school, Lopez learned about a film casting that was seeking several teenage girls for small roles. She auditioned and was cast in My Little Girl (1986), a low-budget film co-written and directed by Connie Kaiserman. Lopez acted as Myra, a young woman at a center for troubled girls. After she finished filming her role in the film, Lopez realized that she wanted to become a "famous movie star". To please her parents, though, she enrolled in Baruch College, only to drop out after one semester. She told her parents about her dream of becoming a movie star, but they insisted that it was a "really stupid" idea and that "no Latinos did that". The differences in opinions led Lopez to move out of their family home and into an apartment in Manhattan. During this period, Lopez performed in regional productions of the musicals Jesus Christ Superstar and Oklahoma!. From there, she was hired for the chorus in a Golden Musicals of Broadway, which toured Europe for five months. She was unhappy with the role, as she was the only member of the chorus not to have a solo. She later got a job on the show Synchronicity in Japan, where she acted as a Dancer, singer, and Choreographer.

Upon launching her music career in the late 1990s, Lopez contributed to the "Latin explosion" occurring in entertainment at the time, with the Daily Herald describing her as "crossover royalty". She was featured on the cover of the first issue of Latina magazine in 1996, with Editor Galina Espinoza stating that there is "no recounting of modern Latina history without Jennifer" in a 2011 editorial praising her legacy. Around the time her career began to burgeon, the emphasis on Lopez's curvaceous figure grew; scholar Sean Redmond wrote that this was a sign of her role and social power in the cultural changes occurring in the United States. In August 2005, Time listed Lopez as one of the most influential Hispanics in America, remarking: "Why? Because over a decade ago, she was an anonymous background Dancer on the second-rated sketch-comedy show. Today she's known by two syllables." In February 2007, People en Español named her the most influential Hispanic entertainer. In 2014, Scientists named a species of aquatic mite found in Puerto Rico, Litarachna lopezae, after Lopez.

Lopez was selected as a backup Dancer for the New Kids on the Block in 1991 and performed with them during their performance of "Games" at the 18th Annual American Music Awards. Shortly after, Lopez gained her first regular high-profile job as a Fly Girl Dancer on the television program In Living Color. She applied for the job after one of the cast members was unable to continue with the show. Out of 2,000 applicants, Lopez made it to the finals. She was the runner-up but eventually received the role when the winner was unable to accept the job. She moved to Los Angeles to film the series and remained a regular cast member until 1993, when she decided to pursue a full-time acting career. Prior to leaving the show, Lopez briefly worked as a backup Dancer for American recording Artist Janet Jackson. Lopez was set to tour with Jackson on her Janet World Tour in late 1993 but backed out as she wanted to do her "own thing".

Lopez has developed an image as a sex symbol and "one of the most desirable women on the planet". She is widely celebrated for her callipygian figure, which was the inspiration for Sir Mix-a-Lot's 1992 hit "Baby Got Back". She has been credited with influencing a change in mainstream female body image. In Latin Sensations (2001), Herón Marquez wrote: "Because she wasn't rail thin, Lopez had broken the mold and allowed millions of women to feel good about their bodies. Suddenly, it was okay for women to have hips, curves, and a big backside." Vanity Fair described her buttocks as "in and of themselves, a cultural icon". Details magazine named Lopez the "Sexiest Woman of the Year" in 1998, and she led FHM's "100 Sexiest Women" list twice. In 2011, she was named "The Most Beautiful Woman" by People. The following year, VH1 ranked her the fourth on their list of "100 Sexiest Artists", while Vibe magazine named her the most "lustable" Celebrity of the past twenty years. In 2014, Lopez stated, "There's this funny notion in America that you can't be a mom and be sexy (...) It's the craziest thing I've ever heard... The truth is that women can be sexy until the day they die."

Lopez received her first professional acting gig in the direct-to-video drama film Lost in the Wild (1993), co-starring with Lindsay Wagner and Robert Loggia. Later in 1993, Lopez signed a deal with CBS to co-star in the television series Second Chances. Lopez received her first major big-screen role in Gregory Nava's 1995 drama My Family portraying Young Maria. Although her role was uncredited, Lopez received an Independent Spirit Award for Best Supporting Female nomination for her performance. In November 1995, Lopez starred in Money Train alongside Wesley Snipes and Woody Harrelson as New York City transit cops. In August 1996, Lopez had a supporting role in the comedy Jack.

In April, Lopez starred in the horror film Anaconda alongside Ice Cube and Jon Voight. Lopez starred alongside Sean Penn and Billy Bob Thornton in the crime film U Turn in October. The film, which is based on the novel Stray Dogs by John Ridley, received somewhat positive reviews from critics. In June, Lopez starred opposite George Clooney in Out of Sight, Steven Soderbergh's adaptation of Elmore Leonard's novel of the same name (1996). Cast as a deputy federal marshal who falls for a charming Criminal, Lopez won rave reviews for her performance. Lopez provided the voice of Azteca in the computer-animated film Antz in October.

Lopez's personal life has attracted widespread media attention. From February 22, 1997, to January 1998, she was married to Cuban waiter Ojani Noa. Since their brief marriage, Lopez has endured many legal troubles regarding her relationship with Noa. In April 2006, she sued to prevent him from publishing a book about their marriage, contending that it violated their confidentiality agreement. The following year, a court-appointed arbitrator issued a permanent injunction forbidding Noa from "criticizing, denigrating, casting in a negative light or otherwise disparaging" Lopez. She was awarded $545,000 in compensatory damages and Noa was ordered to hand over all copies of materials related to the book to Lopez or her attorney. A lawsuit regarding a compromising private honeymoon video in Noa's possession is presently running.

Lopez is regarded as the most influential Hispanic performer in the United States, credited with breaking racial barriers in the entertainment industry. In 1999, The Record newspaper observed that she was responsible for the introduction of a Latina presence in the film industry, which was a "whites-only preserve" for much of its history. Described as a "multidimensional Artist who had turned into a financial powerhouse", Lopez became the highest-paid Actress of Hispanic descent in history. Miriam Jiménez Román stated in The Afro-Latin Reader: History and Culture in the United States (2009) that "[she] was able to traverse the difficult racial boundaries". In 2012, Business magazine Forbes suggested that Lopez "may be the most powerful entertainer on the planet", and named her "the world's most powerful Latino celebrity".

Famed for her distinct style and fashion sense, Us Weekly named Lopez "Style Icon" of the 2000s decade. The Green Versace "Jungle Dress" that she wore at the 42nd Annual Grammy Awards in 2000 was voted the fifth most iconic red carpet dress of all time in a poll run by The Daily Telegraph. The images of Lopez wearing the dress became the most popular search query of all time at that point, and subsequently led to the creation of Google's image search. Her style has influenced a range of celebrities, including Kelly Rowland, Kim Kardashian and Jennifer Love Hewitt. Her record-breaking fragrance line has become the most successful Celebrity line in the world, with sales exceeding $2 billion. Following the success of Lopez's appointment as a judge on American Idol in 2010, a trend of networks hiring "big names" for judging panels on reality shows ensued. The Hollywood Reporter branded this "The J.Lo Effect".

Lopez remains the only female entertainer to have a number one album and film simultaneously in the United States. With her second studio album J.Lo (2001), Lopez became the first female solo recording Artist under Epic Records to achieve a number one album in the United States since its inception in 1953. Her album J to tha L-O! The Remixes was acknowledged by the Guinness World Records as the first number one remix album in the United States. In 2010, Lopez was honored by the World Music Awards with the Legend Award for her contribution to the arts. Lopez's return to prominence the following year with her single "On the Floor"—among the best-selling singles of all time, and its music video recognized as the "Highest Viewed Female Music Video of All Time" by Guinness World Records in 2012—is regarded as one of the greatest musical comebacks in history. In 2013, she was presented with the prestigious landmark 2,500th star on the Hollywood Walk of Fame for her musical contributions, and Univision presented her with the World Icon Award in its Premios Juventud. In 2014, she became the first female recipient of the Billboard Icon Award. Billboard magazine ranked her as the ninth greatest dance club Artist of all time in 2016. In 2017, she was awarded the Telemundo Star Award.

Speaking of Lopez's image, Andrew Barker of Variety observed: "Despite a carefully cultivated image as an imperious pop Empress in ludicrously expensive outfits, her signature hits bear the titles "I'm Real" and "Jenny From the Block". She managed the perilous transition from Actress to music star without ever seeming to pick either as a primary gig. She established herself as an oft-provocative sex symbol while her demeanor made it abundantly clear that she's not asking you to come hither." In 2002, Lynette Holloway of The New York Times described Lopez as overexposed. She wrote: "Forgive yourself if you are seeing Jennifer Lopez in your sleep. She is everywhere." Holloway noted her image to be "a dash of ghetto fabulousness" and "middle-class respectability" for mass appeal. Entertainment Weekly observed a change in her public profile upon joining American Idol in 2011, writing: "Gone was her old cut-a-bitch swagger; J. Lo 2.0 is an all-embracing, Oprahfied earth madre." Lopez is considered an icon of popular culture. Television presenter Ray Martin describes her as a "showbiz phenomenon".

Lopez is a tabloid fixture and has admitted to having a "less-than-perfect" public image. The media often draw comparisons between Lopez and Actress Elizabeth Taylor, due to her numerous failed relationships. In fact, Lopez has been dubbed a "modern-day Liz Taylor" by the media. Lynn Hirschberg of W compared her glamorous public persona to that of Taylor. Her style is described by Billboard's Lauren Savage as scantily clad. Lopez has been criticized by the animal rights organization PETA for inclusion of fur in her fashion lines and outfits. She has received a bad reputation as being a demanding "diva", but she constantly refutes this. In 2003, The Observer remarked that Lopez was "the woman immortalised in a million headlines as 'Hollywood's most demanding diva' ... Lopez must wonder what heinous crime she has committed to become the most vilified woman in modern popular culture."

In March 2004, Lopez had a minor role in the film Jersey Girl, alongside Affleck. Her character, Gertrude Steiney, dies during childbirth within the first 15 minutes of the film. From the intense media scrutiny following the couple's break-up, it was noted that "they may need to put Lopez in a coffin on the poster if they want anyone to come". In October, Lopez co-starred alongside Richard Gere in the drama Shall We Dance?, a re-make of the 1996 Japanese film of the same title. The film was successful at the box office, and was considered a rebound for Lopez following Gigli.

After placing her career on hiatus, Lopez released her fourth studio album, Rebirth, in February 2005. According to Lopez, Rebirth "came about because I was on such a roller-coaster ride, that was my career from my first album to my last album, and I did a bunch of movie projects in between. I finally took some time just for myself, and [when] I came back, this was the first project I did. I felt like it was a new beginning for me, like I was, in a way, reborn." Tracy Hopkins of NBC's Today Music noted that after "fawning" over Affleck on This Is Me... Then", Lopez "wisely keeps her love life out of the spotlight" on Rebirth and only references her relationship with Anthony on a few tracks. The album produced the single "Get Right", which peaked at number one in the United Kingdom. In May, she starred alongside Jane Fonda in the romantic comedy Monster-in-Law, for which she received a salary of $15 million. The film's marketing played up Lopez's "Gigli-and-tabloid tarnished image", and it became a box office success. In August, Lopez starred alongside Robert Redford and Morgan Freeman in An Unfinished Life, a drama film based on the novel of the same name.

In April 2006, Lopez reappeared on the Billboard Hot 100 as a featured Artist on "Control Myself", the lead single from LL Cool J's twelfth studio album Todd Smith. The song peaked at number four on the chart following its release as a music download, making it the pair's second collaboration to reach the top five. Bordertown, a film based on the Female homicides in Ciudad Juárez, made its premiere at the Cannes Film Festival on May 18, 2006. Lopez, who also acts as the film's Producer, stars as Lauren Adrian, an American news reporter for the Chicago Sentinel who wants to be assigned to the Iraq front-lines to cover the war. Bordertown received a direct-to-video release. DanceLife, a reality series following the lives of seven Dancers trying to break into the world of professional dance, aired on MTV from January 15 to March 5, 2007. Lopez produced, created and was featured in the show. According to the album's co-producer Estéfano, Lopez's fifth studio album Como Ama una Mujer would "prove critics wrong" with its "big songs that require a voice"; referring to the criticism of Lopez having a "limited" vocal tone. The album's lead single "Qué Hiciste" reached number one on Billboard's Hot Latin Songs chart. Lopez performed the song on the sixth season of American Idol on April 11, 2007, becoming the first person to perform a Spanish song on the series. The album received the highest first-week sales in the United States for a Spanish album and the highest digital sales.

Following her break-up with Affleck in January 2004, Lopez began dating her longtime friend, Marc Anthony (real name: Marco Antonio Muñiz). The couple wed that June, and lived in Brookville, New York. Two men attempted to ransom a private wedding video that was stolen from the couple for one million dollars; however, they were arraigned in Manhattan Criminal Court on charges of conspiracy, attempted grand larceny and possession of stolen property. On November 7, 2007, during the final night of their co-headlining tour, Lopez and Anthony officially confirmed that they were expecting their first child. The announcement ended months of speculation over the pregnancy. Her father confirmed that the couple were expecting twins, revealing that it runs in the family: "My sister also had twins, so it's a hereditary thing." Lopez, who is a Roman Catholic, has stated that her faith discouraged her from pursuing in vitro fertilization treatment while trying to get pregnant.

Lopez gave birth to a son, Maximilian David, and a daughter, Emme Maribel, in Long Island, New York, on February 22, 2008. The twins were introduced in the March 11, 2008, issue of People, for which the magazine paid a reported $6 million; the photographs of the twins became the most expensive Celebrity picture ever taken at the time. Three years later in July 2011, the couple announced their split, with Anthony filing for divorce in April 2012. Their divorce was finalized on June 16, 2014, with Lopez retaining primary physical custody of the two children. On December 31, 2014, she legally changed her name back to Jennifer Lopez, dropping Anthony's last name (Muñiz).

In 2009, Lopez launched the Lopez Family Foundation (originally known as the Maribel Foundation) alongside her sister, Lynda. The nonprofit organization seeks to increase the availability of Health care for underprivileged women and children, offering a telemedicine program supported by a partnership with the Children's Hospital Los Angeles. The foundation has led to the expansion of medical facilities in Panama and Puerto Rico, and created the Center for a Healthy Childhood at the Montefiore Medical Center in the Bronx.

Lopez parted ways with Epic Records in February 2010, citing that she had fulfilled her contractual obligations and now wished to release her seventh studio album Love? under a new label. Her departure from the label temporarily halted production on the album, which commenced in 2009. Upon signing a new contract with Island Records, recording resumed on the album. The New York Daily News revealed that Lopez would be taking some of the records recorded under Sony Music Entertainment to her new label so that they could be included on the album. In April, Lopez starred in the romantic comedy The Back-up Plan, her first theatrical role in three years. In June, following the departure of Ellen DeGeneres from American Idol, it was reported that Lopez was in talks to join season ten's judging panel. During this same time, Lopez and Anthony were being considered for a role on The X Factor for their appeal to Latin and International markets. It was officially announced in September that Lopez would be joining the tenth season of American Idol. MTV stated that the deal was "mutually beneficial to all those involved", while CNN reported that Lopez was viewing it as a decision to revive her career, while American Idol producers believed that Lopez and Steven Tyler's appointments would strengthen viewing figures. In October, Lopez released her fourteenth fragrance, Love and Glamour. The perfume was inspired by Lopez's forthcoming "return to the spotlight".

On stage, Lopez is recognized for her showmanship and sex appeal, and often includes costumes such as bodysuits as part of her performance. Author Priscilla Peña Ovalle stated in Dance and the Hollywood Latina: Race, Sex and Stardom (2011) that Lopez was one of the Latin stars who "used dance to gain agency as working performers with mainstream careers, yet many of their roles paradoxically racialized and sexualized their bodies". Troy Patterson of Entertainment Weekly also observed that she used her body for emphasis on stage, "She turned herself out as the fly girl hyperversion of postfeminist power, flaunting her control by toying with the threat of excess. In consequence, her star went supernova." Her signature movements include "clock-wise pivoting with salsa hip circles and sequential torso undulations". While being noted to lip sync in the early stages of career, Lopez's Dance Again World Tour was praised for showcasing live vocals and choreography synchronously. In a review of her Las Vegas residency All I Have, Los Angeles Times Writer Nolan Feeney called her "Queen of the Strip" and remarked that her dancing is "undoubtedly the centerpiece of the show".

Lopez endorsed President Barack Obama in his 2012 presidential campaign, speaking in television advertisements and attending a fundraising event for Obama in Paris. She endorsed Democratic presidential nominee Hillary Clinton in 2016, headlining a free concert in Florida in support of her that October.

Lopez's provocative stage performances have also drawn scrutiny at times. In May 2013, her performance on the finale of the television series Britain's Got Talent was deemed inappropriate for family-friendly television, and drew viewer complaints to Ofcom. Following her controversial performance at the musical festival Mawazine in 2015, Moroccan Prime Minister Abdelilah Benkirane called it "indecent" and "disgraceful", while an education group claimed that she "disturbed public order and tarnished women's honor and respect".

Following the September 11 attacks, Lopez was heavily involved in charitable activities. Joining various other artists, she was featured on charitable singles such as "What's Going On" and "El Ultimo Adios (The Last Goodbye)", which benefited people affected by the tragedy. One dollar from each ticket sold at Lopez and Anthony's co-headlining North American concert tour, which grossed an estimated $10 million, was donated to Run for Something Better—a charitable organization supporting physical fitness programs for children. In February 2007, Lopez was honored with the Artists for Amnesty prize by the human rights organisation Amnesty International, for her work in the film Bordertown, which shed light on the hundreds of female homicides in Ciudad Juárez. Lopez described it as "one of the world's most shocking and disturbing, underreported crimes against humanity."

January 2015 saw the release of The Boy Next Door, an erotic thriller that Lopez both co-produced and starred in as a high school Teacher who becomes involved with a student, which eventually leads to his dangerous obsession with her. The film received negative reviews from critics. Despite this, it became her most successful opening at the box office for a live action film since Monster-in-Law, and ultimately grossed over $55 million at the global box office, against a production budget of $4 million. The following month, she unveiled her next fragrance, JLuxe. Lopez had a voice role in the animated feature Home, alongside Steve Martin, Jim Parsons, and Rihanna, and released in March 2015. She contributed the single "Feel the Light" to the film's official Soundtrack. Lopez also starred in the independent drama film Lila & Eve, alongside Viola Davis. With annual earnings of $28.5 million, she was ranked as the seventh highest-paid woman in music for 2015.

Lopez stars as Detective Harlee Santos in NBC's crime drama series Shades of Blue (also serving as an executive producer), a single mother and police detective who goes undercover for the FBI to investigate her own squad. It premiered on January 7, 2016, giving the network its most-watched Thursday debut in seven years with 8.6 million viewers. Lopez's performance received positive reviews. Shades of Blue was renewed for a second season, which premiered in March 2017. That same month, the series was renewed for a third season. In May 2015, she announced her Las Vegas residency concert show, which commenced on January 20, 2016, the first of twenty initial dates. Titled All I Have, it takes place at Planet Hollywood's The AXIS theater. The residency has been lucrative, and Lopez signed a three-year contract which will see her perform 120 shows. In March 2016, six years after announcing her departure, she announced her return to Epic Records, signing a multi-album deal with the label. Her first single since returning to Epic, "Ain't Your Mama", was released the following month. With earnings of $39.5 million, she was among the highest-paid female artists from June 2015 to June 2016. Lopez reprised her voice role as Shira in the animated film Ice Age: Collision Course, which was released in July 2016.

Lopez is working on her second full length Spanish album, which is set to be released through Sony Music Latin; Marc Anthony serves as an executive Producer for the project. It is titled Por Primera Vez, which translates to For the First Time in English. The album's lead single, "Ni Tú Ni Yo" (featuring Cuban reggaeton group Gente de Zona), was released on in July 2017. The second single "Amor, Amor, Amor" featuring Wisin followed in November 2017.

In March 2018, Lopez opened up about her own Me Too movement story of being sexually harassed by a Director early on in her career, when she was asked to take her top off during one of her first films. Lopez has also been an active advocate for the Time's Up movement.

Lopez is set to star in the comedy film Mothers I'd Like To..., for which she will also serve as a Producer through her production company. She will star as drug lord Griselda Blanco in a television film for HBO, which will focus on the "rise and fall" of Blanco. She will once more serve as an executive Producer for the film, which is currently in development. She will also produce and star in a romantic comedy film Second Act, which will be directed by Peter Segal. As an executive Producer, Lopez is also developing an untitled legal drama for CBS and Futuristic drama series entitled C.R.I.S.P.R. for NBC. Sometime in 2019, Lopez is set to executive produce and star in NBC's Bye Bye Birdie Live!, a live television production of the stage musical of the same name.