Wong Kar-wai was born on 17 July 1958 in Shanghai, the youngest of three siblings. His father was a Sailor and his mother was a housewife. By the time Wong was five years old, the seeds of the Cultural Revolution were beginning to take effect in China and his parents decided to relocate to British-ruled Hong Kong. The two older children were meant to join them later, but the borders closed before they had a chance and Wong did not see his brother or sister again for ten years. In Hong Kong, the family settled in the Tsim Sha Tsui district, and his father got work managing a night club. Being an only child in a new city, and speaking only Mandarin, Wong has said he felt isolated during his childhood; he struggled to learn Cantonese and English, only becoming fluent in these new languages when he was a teenager.

For his follow-up film, Wong decided to move away from the crime trend in Hong Kong cinema, to which he felt indifferent. He was eager to make something more unusual, and the success of As Tears Go By made this possible. Developing a more personal project than his previous film, Wong picked the 1960s as a setting – evoking an era that he remembered well and had a "special feeling" for. Days of Being Wild focuses on a disillusioned young adult named Yuddy and those around him. There is no straightforward plot or obvious genre, but Stephen Teo sees it as a film about the "longing for love". Andy Lau, Maggie Cheung, and Jacky Cheung rejoined Wong for his second film, while Leslie Cheung was cast in the central role. Hired as Cinematographer was Christopher Doyle, who became one of Wong's most important collaborators, photographing his next six films.

Maggie Cheung and Tony Leung Chiu-wai play the lead characters, who move into an apartment building on the same day in 1962 and discover that their spouses are having an affair; over the next four years they develop a strong attraction. Teo writes that the film is a study of "typical Chinese reserve and repressed desire", while Schneider describes how the "strange relationship" is choreographed with "the grace and rhythm of a waltz" and depicted in "a dreamlike haze by an eavesdropping camera".

As a youth, Wong was frequently taken to the cinema by his mother and exposed to a variety of films. He later said: "The only hobby I had as a child was watching movies". At school he was interested in graphic design, and earned a diploma in the subject from Hong Kong Polytechnic in 1980. After graduating, Wong was accepted onto a training course with the TVB television network, where he learned the processes of media production.

He soon began a screenwriting career, firstly with TV series and soap operas, such as Don't Look Now (1981), before progressing to film scripts. He worked as part of a team, contributing to a variety of genres including romance, comedy, thriller, and crime. Wong had little enthusiasm for these early projects, described by film scholar Gary Bettinson as "occasionally diverting and mostly disposable", but continued to write throughout the 1980s on films including Just for Fun (1983), Rosa (1986), and The Haunted Cop Shop of Horrors (1987). He is credited with ten screenplays between 1982 and 1987, but claims to have worked on about fifty more without official credit. Wong spent two years co-writing the screenplay for Patrick Tam's action film Final Victory (1987), for which he was nominated at the 7th Hong Kong Film Awards.

By 1987 the Hong Kong film industry was at a peak, enjoying a considerable level of prosperity and productivity. New Directors were needed to maintain this success, and – through his links in the industry – Wong was invited to become a partner on a new independent company, In-Gear, and given the opportunity to direct his own picture. Gangster films were popular at the time, in the wake of John Woo's highly-successful A Better Tomorrow (1986), and Wong decided to follow suit. Specifically, unlike Hong Kong's other crime films, he chose to focus on young Gangsters. The film, named As Tears Go By, tells the story of a conflicted youth who has to watch over his hot-headed friend.

Because he was well acquainted with the Producer, Alan Tang, Wong was given considerable freedom in the making of As Tears Go By. His cast included what he considered some of "the hottest young idols in Hong Kong": singer Andy Lau, Maggie Cheung, and Jacky Cheung. As Tears Go By was released in June 1988 and was popular with audiences. It was also a critical success, as several journalists named Wong among the "Hong Kong New Wave". While it was a conventional crime film, critic David Bordwell said that Wong "[stood] out from his peers by abandoning the kinetics of comedies and action movies in favour of more liquid atmospherics." As Tears Go By received no attention from Western critics upon its initial release, but was selected to be screened during Directors' Fortnight of the 1989 Cannes Film Festival.

While his reputation grew steadily throughout the early 1990s, Wong's international standing was "thoroughly consolidated" with the 1997 romantic drama Happy Together (1997). Its development was influenced by the Handover of Hong Kong from Britain to China, which occurred that year. Wong was widely expected to address the event in his next film; instead, he avoided the pressure by choosing to shoot in Argentina. The issues of the Handover were nevertheless important: knowing that homosexuals in Hong Kong faced uncertainty after 1997, Wong decided to focus on a relationship between two men. He was keen to present the relationship as ordinary and universal, as he felt Hong Kong's previous LGBT films had not.

Struggling to get support for his work, in 1992 Wong formed his own production company, Jet Tone Films, with Jeff Lau. In need of further backing, Wong accepted a studio's offer that he make a wuxia (ancient martial arts) film based on the popular novel The Legend of the Condor Heroes by Jin Yong. Wong was enthusiastic about the idea, claiming he had long wanted to make a costume drama. He eventually took little from the book other than three characters, and in 1992 began experimenting with several different narrative structures to weave what he called "a very complex tapestry". Filming began with another all-star cast: Leslie, Maggie, and Jacky Cheung returned alongside Brigitte Lin, Carina Lau, Charlie Young, and Tony Leung Chiu-wai − the latter of which became one of Wong's key collaborators.

Set during the Song dynasty, Ashes of Time concerns a desert-exiled Assassin who is called upon by several different characters while nursing a broken heart. It was a difficult production and the project was not completed for two years, at a cost of HK$47 million. Upon release in September 1994, audiences were confused by the film's vague plotting and atypical take on wuxia. Film scholar Martha P. Nochimson has called it "the most unusual martial arts film ever made", as fast-paced action scenes are replaced with character ruminations and story becomes secondary to the use of colour, landscape, and imagery. As such Ashes of Time was a commercial failure, but critics were generally appreciative of Wong's "refusal to be loyal to [the wuxia] genre". The film won several local awards, and competed at the Venice Film Festival where Christopher Doyle won Best Cinematography. In 2008, Wong reworked the film and re-released it as Ashes of Time Redux.

Fallen Angels is broadly considered a crime thriller, and contains scenes of extreme violence, but is atypical of the genre and heavily infused with Wong's fragmented, experimental style. The loose plot again involves two distinct, subtly overlapping narratives, and is dominated by frantic visuals. The film mostly occurs at night and explores the dark side of Hong Kong, which Wong planned intentionally to balance the sweetness of Chungking: "It's fair to show both sides of a coin". Takeshi Kaneshiro and Charlie Young were cast again, but new to Wong's films were Leon Lai, Michelle Reis and Karen Mok. Upon release in September 1995, several critics felt that the film was too similar to Chungking Express and some complained that Wong had become self-indulgent. Film historians Zhang Yingjin and Xiao Zhiwei commented: "While not as groundbreaking as its predecessors, the film is still different and innovative enough to confirm [Wong's] presence on the international scene" Since its release, Fallen Angels has been considered to be one of Wong's greatest and most influential works, along with Chungking Express and In the Mood For Love.

Wong is an important figure in contemporary cinema, regarded as one of the best filmmakers of his generation. His reputation as a maverick began early in his career: in the 1996 Encyclopedia of Chinese Film, Wong was described as having "already established a secure reputation as one of the most daring avant-garde filmmakers" of Chinese cinema. Authors Zhang and Xiao concluded that he "occupies a special place in contemporary film history", and had already "exerted a sizeable impact". With the subsequent release of Happy Together and In the Mood For Love, Wong's international standing grew further, and in 2002 voters for the British Film Institute named him the third greatest Director of the previous quarter-century. In 2015, Variety named him an icon of arthouse cinema.

Outside of cinema, Wong has been heavily influenced by literature. He has a particular affinity for Latin American Writers, and the fragmentary nature of his films came primarily from the "scrapbook structures" of novels by Manuel Puig and Julio Cortázar, which he attempted to emulate. Haruki Murakami, particularly his novel Norwegian Wood, also provided inspiration, as did the writing of Liu Yichang. The television channel MTV was a further influence on Wong. He said in 1998, "in the late eighties, when it was first shown in Hong Kong, we were all really impressed with the Energy and the fragmented structure. It seemed like we should go in this direction."

Before starting on his next feature, Wong worked on the anthology film Eros (2004), providing one of three short films (the others directed by Michelangelo Antonioni and Steven Soderbergh) that centre on the theme of lust. Wong's segment, titled "The Hand", starred Gong Li as a 1960s call girl and Chang Chen as her potential client. Although Eros was not well received, Wong's segment was often called the most successful.

In his 2005 monograph, Brunette gives the opinion that Happy Together marked "a new stage in [Wong's] artistic development", and along with its successor – In the Mood For Love (2000) – showcases the Director at "the zenith of his cinematic art." The latter film emerged from a highly complicated production history that lasted two years. Several different titles and projects were planned by Wong before they evolved into the final result: a romantic melodrama set in 1960s Hong Kong that is seen as an unofficial sequel to Days of Being Wild. Wong decided to return to the era that fascinated him, and reflected his own background by focusing on Shanghainese émigrés.

Wong's oeuvre consists of ten directed features, 16 films where is he credited only as Screenwriter, and seven films from other Directors that he has produced. He has also directed commercials, short films, and music videos, and contributed to two anthology films. He has received awards and nominations from organisations in Asia, Europe, North America, and South America. In 2006, Wong accepted the National Order of the Legion of Honour: Knight (Lowest Degree) from the French Government. In 2013, he was bestowed with the Order of Arts and Letters: Commander (Highest Degree) by the French Minister of Culture. The International Film Festival of India gave Wong a Lifetime Achievement Award in 2014.

In the 2012 Sight & Sound poll – whereby industry professionals submit ballots to determine the greatest films of all time – In the Mood For Love was ranked 24th, the highest ranked film since 1980 and the sixth greatest film by a living Director. Chungking Express and Days of Being Wild both ranked in the top 250; Happy Together and 2046 in the top 500; and Ashes of Time and As Tears Go By also featured (all but two of Wong's films to that point) . Directors influenced by Wong include Quentin Tarantino, Sofia Coppola, Lee Myung-se, Tom Tykwer, Zhang Yuan, Tsui Hark., and Barry Jenkins.

Though Wong admits to being controlling, and oversees every aspect the filmmaking process, he has formed several long-lasting partnerships and close collaborators. In 2013 he said, "It is always good to work with a very regular group of people because we know how high we can fly and what are the parameters, and it becomes very enjoyable." Two men have been instrumental in developing and achieving his aesthetic: production designer william Chang and Cinematographer Christopher Doyle. Chang has worked on every Wong film and is a trusted confidant, responsible for all set design and costuming. Doyle photographed seven of his projects, all from Days of Being Wild to 2046. Stephen Schneider writes that he deserves "much credit" in Wong's success, as his "masterful use of light and colour renders every frame a work of art". Wong's other regular colleagues include writer-producer Jeffrey Lau, Producer Jacky Pang, and assistant Director Johnnie Kong.

In September 2017 Amazon Video issued a straight-to-series order for Tong Wars, a television drama to be directed by Wong. It focuses on the gang wars that occurred in nineteenth-century San Francisco. Regarding his next film, the Asian media has reported that it will be titled Blossoms and based on a book by Jin Yucheng, which focuses on numerous characters in Shanghai from the 1960s to the 2000s. When asked about his career in 2014, Wong told The Independent, "To be honest with you, I feel I’m only halfway done."

Wong often casts the same actors. He is strongly associated with Tony Leung Chiu-wai, who has appeared in every film apart from As Tears Go By and My Blueberry Nights. Wong describes him as a partner, stating, "I feel like there is a lot of things between me and Tony that is beyond words. We don’t need meetings, talks, whatever, because a lot of things are understood." Other actors who have appeared in at least three of his films are Maggie Cheung, Chang Chen, Leslie Cheung, Jacky Cheung, and Carina Lau.