Norwood was born on February 11, 1979, in McComb, Mississippi, the daughter of Willie Norwood, a former gospel singer and choir Director, and his wife, Sonja Norwood (née Bates), a former district manager for H&R Block. She is the older sister of entertainer Ray J, as well as a cousin of Rapper Snoop Dogg and WWE Wrestler Sasha Banks. Raised in a Christian home, Norwood started singing through her father's work as part of the local church choir, performing her first gospel solo at the age of two. In 1983, her parents relocated to Los Angeles, California, where Norwood was schooled at the Hollywood High Performing Arts Center. Norwood's interest in music and performing increased after becoming a fan of singer Whitney Houston at the age of seven, but at school, she experienced trouble with persuading teachers to send her on auditions as she found no support among the staff. Norwood began entering talent shows by the time she was eleven, and, as part of a youth singing group, performed at several public functions.

In 1990, her talent led to a contract with Teaspoon Productions, headed by Chris Stokes and Earl Harris, who gave her work as a backing vocalist for their R&B boy band Immature, and arranged the production of a demo tape. In 1993, amid ongoing negotiations with East West Records, Norwood's parents organized a recording contract with the Atlantic Recording Corporation after auditioning for the company's Director of A&R Darryl Williams. To manage her daughter, Norwood's mother soon resigned from her job, while Norwood herself dropped out of Hollywood High School later, and was tutored privately from tenth grade on. During the early production stages of her debut album, Norwood was selected for a role in the ABC sitcom Thea, portraying the daughter of a single mother played by Comedian Thea Vidale. Initially broadcast to high ratings, the series' viewership dwindled and ended up running for only one season, but earned her a Young Artists Award nomination for Outstanding Youth Ensemble alongside her co-stars. Norwood recalled that she appreciated the cancellation of the show as she was unenthusiastic about acting at the time, and the taping caused scheduling conflicts with the recording of her album. She stated, "I felt bad for everybody else but me. It was a good thing, because I could do what I had to do, because I wanted to sing."

Since her 1994 debut album, Norwood has sold over 40 million records worldwide. The Recording Industry Association of America (RIAA) lists Norwood as one of the top selling artists in the United States, with 10.5 million certified albums, She has sold over 8.62 million albums, Her song The Boy Is Mine is also one of the longest running number one songs in the United States, and is one of the best selling duets of all time. In 1999, Billboard ranked Norwood among the top 20 of the Top Pop Artists of the 1990s. In 2010, Billboard included Norwood in their Top 50 R&B and Hip Hop Artists list of the past 25 years. Norwood was one of the youngest artists nominated for the Grammy Award for Best New Artist. Her second album Never Say Never appeared in the "Top 100 Certified Albums" list by the RIAA.

Brandy went on to sell over six million copies worldwide, and produced three top ten hits on the Billboard Hot 100, including "I Wanna Be Down" and "Baby", both of which reached the top of the Hot R&B Singles chart and were certified platinum by the Recording Industry Association of America. "Brokenhearted", a duet with Wanya Morris of Boyz II Men, became a number-two hit on the charts. The album earned Norwood two Grammy Award nominations for Best New Artist and Best Female R&B Vocal Performance the following year, and won her four Soul Train Music Awards, two Billboard Awards, and the New York Children's Choice Award. In 1995, she finished a two-month stint as the opening act on Boyz II Men's national tour, and contributed songs to the soundtracks of the films Batman Forever and Waiting to Exhale, with the single "Sittin' Up in My Room" becoming another top-two success. In 1996, Norwood also collaborated with Tamia, Chaka Khan, and Gladys Knight on the single "Missing You", released from the Soundtrack of the F. Gary Gray film Set It Off. The single won her a third Grammy nomination in the Best Pop Collaboration with Vocals category.

In 1996, Norwood along with her brother Ray J, created the Norwood Kids Foundation. Its goal of is to "use performing arts as a catalyst to shape the youth of today into self-confident, disciplined, responsible, and caring individuals capable of making a positive impact in their communities." In 1999 Brandy was the first international spokesman person for youth by UNICEF. Norwood is also an avid supporter of the Make A Wish Foundation and RAINN. In 2000, Brandy donated $100,000 to 2000 WATTS, an entertainment community center founded by singer Tyrese Gibson in the underprivileged community of Watts, California. Brandy teamed up with Skecher's “Nothing Compares to Family” campaign in 2008. In 2010 Norwood became involved with Get Schooled, a national non-profit mobile phone calls by celebrities to wake up students for school. In 2014, Norwood teamed up with "text4baby", which spreads health and wellness to expecting moms via text message, and became an honorary co-chairman of the 2014 Unstoppable Foundation.

American neo soul singer Erykah Badu noted that her 1997 debut album, Baduizm, was partly influenced by Norwood's debut album, while Barbadian singer Rihanna said of her 2007 album Good Girl Gone Bad, "[Brandy] really helped inspire that album. I listened to [Afrodisiac] every day [while in the studio]." Kelly Rowland cited Norwood, who also wrote and produced for Rowland's debut album, as one of the inspirations for her second studio album Ms. Kelly (2007). Rock musician John Frusciante, former Guitarist of rock group Red Hot Chili Peppers cited Norwood as the "main inspiration" behind the guitar work on Red Hot Chili Peppers' 2006 album, Stadium Arcadium.

Fledgling Producer Rodney "Darkchild" Jerkins was consulted to contribute to Norwood's second album Never Say Never, which was released in June 1998. Norwood co-wrote and produced six songs on the album which yielded her first number-one song on the U.S. Billboard Hot 100, "The Boy Is Mine", a duet with singer Monica that has become the most successful song by a female duo in the music industry. Exploiting the media's presumption of a rivalry between the two young Singers, the song was one of the most successful records in the United States of all time, spending a record-breaking thirteen weeks atop the Billboard charts, and eventually garnering the pair a Grammy Award for Best R&B Performance by a Duo or Group with Vocal. The album's success was equally widespread, and after extensive radio play of the single overseas, the label released it globally during the summer. Never Say Never eventually became Norwood's biggest-selling album, selling over 16 million copies worldwide. Critics rated the album highly, with AllMusic's Stephen Thomas Erlewine praising Norwood and her team for wisely finding "a middle ground between Mariah Carey and Mary J. Blige—it's adult contemporary with a slight streetwise edge." Altogether, the album spawned seven singles, including Norwood's second number-one song, the Diane Warren-penned "Have You Ever?" She also embarked on the successful Never Say Never World Tour in 1998, consisting of sold out performances in Europe, Asia, and the United States.

Norwood has had many endorsements in her career. In 1999, she became a CoverGirl, appearing in a number of commercials. She also represented the brands Candie's in 1998 and DKNY in the Spring of 2000. In the late 1990s Norwood was represented by Wilhelmina Agency, one of the leading modeling agencies in the industry. In 1999, Mattell released the Brandy Doll. The doll featured Norwood in a reddish orange blouse and orange long skirt. Next to this, the Holiday Brandy Doll was released in 2000 along with another "Brandy Doll". Millions of the dolls were sold and they were one of the biggest selling toys for Mattel. In 2005, Brandy became the spokesperson for Ultima, a company for hair weaves and wigs. As of 2014, she no longer represents them.

Songwriter Sean Garrett credits the vocal work on the album Full Moon for his approach to writing, saying "I take a lot from what [Brandy] and Rodney did on the Full Moon album. I was extremely impressed with it and I always try to outdo that album". B.Slade spoke of the album, commenting Full Moon single-handedly changed the vocal game. "It has been the template for vocal choices and background vocal arrangements [for years]." R&B singer Melanie Fiona, especially admired the singer's work on that album. Neo soul singer India.Arie often cites the album, particularly the song "He Is" as being the template for a wide array of Singers." The oft-praised vocal work on the album sparked the idea of Norwood gaining the subjective nickname the "vocal bible". Canadian R&B singer Keshia Chanté credited the album for inspiring her writing for her album Night & Day, while American singer Luke James referred to Full Moon as the "bible" of 2000s contemporary R&B, calling it the "blueprint of how to do vocals."

After a lengthy hiatus following the end of Moesha, and a number of tabloid headlines discussing her long-term battle with dehydration, Norwood returned to music in 2001, when she and brother Ray-J were asked to record a cover version of Phil Collins' 1990 hit "Another Day in Paradise" for the tribute album Urban Renewal: A Tribute to Phil Collins. Released as the album's first single in Europe and Oceania, the song became an instant international success overseas, scoring top-ten entries on the majority of all charts it appeared on. Full Moon, Norwood's third studio album, was released in February 2002. It was composed of R&B and pop-oriented songs, many of them co-created with Jerkins, Warryn Campbell and Mike City. Its lead single "What About Us?" became a worldwide top-ten hit, and the album's title track was a Top 20 hit in the United States and the UK. Media reception was generally lukewarm, with Rolling Stone describing the album as "frantic, faceless, fake-sexy R&B." Within the coming year, Norwood and Robert "Big Bert" Smith began writing and producing for other artists such as Toni Braxton, Kelly Rowland, and Kiley Dean. Norwood's foray into reality television began in 2002 with the MTV series Diary Presents Brandy: Special Delivery; the show documented the final months of Norwood's pregnancy with her daughter Sy'rai.

During the production of her album Full Moon in mid-2001, Norwood became romantically involved with Producer Robert "Big Bert" Smith. The couple kept their relationship secret until February 2002, when Norwood announced that she was expecting her first child. However, a year after the birth of their daughter, Sy'rai Iman Smith, on June 16, 2002, an event tracked by the four-part MTV reality series Brandy: Special Delivery—Norwood and Smith separated. In 2004, Smith revealed that the pair had never been legally wed, but that they had pretended to marry to preserve Norwood's public image. Norwood later stated that she regarded her relationship with Smith as a "spiritual union and true commitment to each other."

By the following year, Norwood had begun a relationship with NBA guard Quentin Richardson, who was then playing for the Los Angeles Clippers. The couple soon became engaged in July 2004 but Norwood eventually ended their 15-month engagement in October 2005. It was reported that Norwood had to get a tattoo of Richardson's face on her back transformed into a cat. In 2010, she briefly dated Rapper Flo Rida. At the end of 2012, Norwood became engaged to music executive Ryan Press. In April 2014, Norwood called off her engagement with Press following their breakup earlier that year.

Driving home on December 30, 2006, Norwood was involved in a fatal automobile collision on Los Angeles' San Diego (405) Freeway. 38-year-old Awatef Aboudihaj was the driver of a Toyota which was struck by Norwood's Range Rover. Aboudihaj died from her injuries at the L.A. Holy Cross Hospital the following day.

Nevertheless, there have been multiple lawsuits filed against Norwood, all of which were ultimately settled out of court by her attorney Ed McPherson. Aboudihaj's parents filed a $50 million wrongful death lawsuit against Norwood. Filed on January 30, 2007, the lawsuit was initially set to go to trial in April 2009, but was eventually canceled as Norwood had settled out of court with Aboudihaj's parents. Aboudihaj's husband also filed a lawsuit against Norwood, suing her for an undisclosed amount of financial relief to cover medical and funeral expenses, as well as legal costs and other damages. He rejected his part of a $1.2 million settlement offer in February 2009, but did settle in November of that year. The couple's two children, who also filed a lawsuit against Norwood, received $300,000 each, according to court documents filed in L.A. County Superior Court on June 2, 2009. Two other drivers who were involved and injured in the accident also filed a lawsuit against Norwood. They settled with Norwood for undisclosed amounts.

Norwood's fifth studio album, Human, was released in December 2008, produced by Toby Gad, Brian Kennedy, and Redone. Distributed by Koch Records and Sony Music, the album marked Norwood's debut on the Epic Records label, and her reunion with long-time contributor and mentor Rodney Jerkins, who wrote and executive produced most of the album. Generally well received by critics, Human debuted at number fifteen on the U.S. Billboard 200 with opening week sales of 73,000 copies. With a domestic sales total of 214,000 copies, it failed to match the success of its predecessors. While lead-off single "Right Here (Departed)" scored Norwood her biggest chart success since 2002's "Full Moon", the album failed to impact elsewhere, resulting in lackluster sales in general and the end of her contract with the label, following the controversial appointment of Amanda Ghost as President of Epic Records, and Norwood's split with Rapper Jay-Z's Roc Nation management.

In December 2009, she officially introduced her rapping alter-ego Bran'Nu with two credits on Timbaland's album Timbaland Presents Shock Value 2, and was cast in the pilot episode for the ABC series This Little Piggy, also starring Rebecca Creskoff and Kevin Rahm, which was recast the following year.

In fall 2010, Norwood appeared as a contestant on season 11 of the ABC reality show Dancing with the Stars, partnered with Maksim Chmerkovskiy. She ultimately placed fourth in the competition, which was a shock to the judges, viewers, studio audience, and other contestants that considered her one of the show's frontrunners throughout the entire competition. In August 2011, it was confirmed that Norwood had signed a joint record deal with RCA Records and Producer Breyon Prescott's Chameleon Records. In September, a new talent show, Majors & Minors, created by musician Evan Bogart, premiered on The Hub. It followed a group of young performers age 10–16 and their chance to be mentored by some established artists such as Norwood, Ryan Tedder and Leona Lewis. Later that same year, Norwood returned to acting roles with recurring appearances on The CW's teen drama series 90210, and in the fourth season of the Lifetime's comedy series Drop Dead Diva, in which she played the role of Elisa Shayne.

In 2011, Norwood joined the cast of the BET comedy series The Game, playing the recurring role of Chardonnay, a bartender. She became a regular cast member by the next season. In February 2012, Norwood reteamed with Monica on "It All Belongs to Me", which was released as a single from the latter's album New Life. Norwood's own comeback single "Put It Down" featuring singer Chris Brown was released later that year. The song reached number three on Billboard's Hot R&B/Hip-Hop Songs chart, becoming her first top ten entry in ten years. Her sixth album Two Eleven, which was released in October, saw a return to her R&B sound, but with what Norwood described a "progressive edge". A moderate commercial success, it was viewed as a humble comeback from Norwood, reaching number three on the US Billboard 200, and the top of the Billboard US Top R&B/Hip-Hop Albums chart.

In March 2013, Norwood returned to film, joining an ensemble cast consisting of Jurnee Smollett-Bell, Lance Gross and Vanessa L. Williams in Tyler Perry's drama Temptation: Confessions of a Marriage Counselor. Norwood plays supporting character Melinda, a woman with secrets. The film received generally negative reviews from critics but became a moderate US box office success. In June 2013, Norwood signed with Creative Artists Agency, headquartered in Los Angeles, and in early 2014, she arranged a management deal with MBK Entertainment with CEO Jeff Robinson. In July, she was also inducted as an honorary member of Alpha Kappa Alpha sorority. The same month, Norwood released a cover version of Coldplay's song "Magic" to her TwitMusic account; it peaked at number one on Billboard's Trending 140 chart. Also in 2014, Norwood made guest appearances on VH1's Love and Hip Hop: Hollywood and the TV Land sitcom The Soul Man. At the 2014 BET Hip Hop Awards, she reunited with Queen Latifah, MC Lyte, and Yo-Yo to perform the hip hop remix of "I Wanna Be Down" in celebration of its 20th anniversary.

Afrodisiac has been credited as one of predecessors to the Alternative R&B subgenre. In a 2014 music and fashion conversation with NPR, singer and model Solange discussed the album, saying "Brandy is really the foundation of a lot of this very innovative, progressive, experimental R&B. Brandy really influenced a lot of that. Frank Ocean will say it. Miguel will say it."

After finishing the filming of the final season of The Game, Norwood made her Broadway debut in the musical Chicago, in which she played the lead role of Roxie Hart, beginning in April 2015. Although initially a six-week run, her engagement was extended until August 2015. Norwood also reprised the role in the musical's national tour during its 2016 engagement in Los Angeles and again played the role during the tour's stop in Washington D.C. She will return to the Broadway production for a limited 17-performance only engagement, lasting from August 17 to 31, 2017. Also in 2015, Norwood appeared on the 99 Souls mashup single "The Girl Is Mine", for which she re-recorded her vocals from "The Boy Is Mine." The song reached the top 10 in the United Kingdom and top 40 on other international charts, where it became her highest-charting single in years.

In February 2016, Norwood announced her Slayana World Tour, which highlighted stops in both Europe and Oceania. Her first headlining tour in eight years, it was ended ahead of schedule on June 30 after Norwood was hospitalized due to exhaustion. In March, Norwood sued Chameleon Entertainment Group and its President, Breyon Prescott, after the label reportedly refused to allow her to record and release new albums. In November 2016, Norwood became the second recipient of the Lady of Soul Award at the Soul Train Music Awards. Her stripped-down nine-minute song medley was met with overwhelming praise.

Norwood has also made her impact in the film and television industry as well. Norwood was the first African American to play the role of Cinderella. Her role as Cinderella inspired many African American actors. Speaking on the role, Keke Palmer said "I feel like the reason I'm able to do this [becoming the first African American Cinderella on Broadway] is definitely because Brandy did it on TV". Norwood's TV-show Moesha on UPN was also one of the longest-running Black sitcoms of all time. On stage, Norwood made Broadway history along with co-star Lana Gordan by becoming the first black co-leads in Chicago the Musical in 2017.

Brandy also names her father, vocal coach Willie Norwood, as instrumental to her discovery and development as a musician. She exclaims that her dad “taught me everything that I know [about singing]”. About her dad, Brandy states: “I grew up singing in church with my dad, where he was the musical Director and we sang gospel songs in acapella almost exclusively. He bought me my first 4-track tape recorder. At first, I didn’t like my own voice, but he encouraged me to embrace the unique qualities of my voice.”