Baker was born and raised in a musical household in Yale, Oklahoma; his father, Chesney Baker, Sr., was a professional guitar player, and his mother, Vera (née Moser) was a talented pianist who worked in a perfume factory. His maternal grandmother, Randi Moser, was Norwegian. Baker began his musical career singing in a church choir. His father introduced him to brass instruments with a trombone, which was replaced with a trumpet when the trombone proved too large.  Baker received some musical education at Glendale Junior High School, but left school at age 16 in 1946 to join the United States Army. He was posted to Berlin, where he joined the 298th Army band. After leaving the army in 1948, he studied theory and harmony at El Camino College in Los Angeles. He dropped out in his second year, however, re-enlisting in the army in 1950. Baker became a member of the Sixth Army Band at the Presidio in San Francisco, but was soon spending time in San Francisco jazz clubs such as Bop City and the Black Hawk. Baker once again obtained a discharge from the army to pursue a career as a professional musician.

Baker’s earliest notable professional gigs were with saxophonist Vido Musso’s band, and also with tenor saxophonist Stan Getz, though he earned much more renown in 1952 when he was chosen by Charlie Parker to play with him for a series of West Coast engagements.  In 1952, Baker joined the Gerry Mulligan Quartet, which was an instant phenomenon. Several things made the Mulligan/Baker group special, the most prominent being the interplay between Mulligan’s baritone sax and Baker’s trumpet. Rather than playing identical melody lines in unison like bebop giants Charlie Parker and Dizzy Gillespie, the two would complement each other’s playing with contrapuntal touches, and it often seemed as if they had telepathy in anticipating what the other was going to play next. The Quartet’s version of “My Funny Valentine”, featuring a Baker solo, was a hit, and became a tune with which Baker was intimately associated.

The Quartet found success quickly, but lasted less than a year because of Mulligan’s arrest and imprisonment on drug charges. Baker formed his own quartet with pianist and composer Russ Freeman in 1953, along with bassists Carson Smith, Joe Mondragon, and Jimmy Bond and drummers Shelly Manne, Larry Bunker, and Bob Neel. The Chet Baker Quartet found success with their live sets, and they released a number of popular albums between 1953 and 1956. In 1953 and 1954, Baker won the Down Beat and Metronome magazines’ Readers Jazz Polls, beating the era’s two top trumpeters, Miles Davis and Clifford Brown. Down Beat readers also voted Baker as the top jazz vocalist in 1954. In 1956, Pacific Jazz released Chet Baker Sings, a record that increased his profile but alienated traditional jazz fans; he would continue to sing throughout his career.  Due to Baker’s chiseled features, he was approached by Hollywood studios, and he made his acting debut in the film Hell’s Horizon, released in the fall of 1955. He declined an offer of a studio contract, preferring life on the road as a musician. Over the next few years, Baker fronted his own combos, including a 1955 quintet featuring Francy Boland, where Baker combined playing trumpet and singing. He became an icon of the West Coast “cool school” of jazz, helped by his good looks and singing talent. Baker’s 1956 recording, released for the first time in its entirety in 1989 as The Route, with Art Pepper, helped further the West Coast jazz sound and became a staple of cool jazz.

Baker began using heroin in the 1950s, resulting in an addiction that lasted the remainder of his life. At times, Baker pawned his instruments for money to maintain his drug habit. In the early 1960s, he served more than a year in prison in Italy on drug charges; he was later expelled from both West Germany and the UK for drug-related offenses. Baker was eventually deported from West Germany to the United States after running afoul of the law there a second time. He settled in Milpitas in northern California, where he played in San Jose and San Francisco between short jail terms served for prescription fraud.  In 1968, Baker was savagely beaten (allegedly while attempting to buy drugs) after a gig in The Trident restaurant in Sausalito, California sustaining severe cuts on the lips and broken front teeth, which ruined his embouchure. He stated in the film Let’s Get Lost that an acquaintance attempted to rob him one night but backed off, only to return the next night with a group of several men who chased him. He entered a car and became surrounded. Instead of rescuing him, the people inside the car pushed him back out onto the street, where the chase by his attackers continued, and subsequently he was beaten to the point that his teeth, never in good condition to begin with, were knocked out, leaving him without the ability to play his horn. He took odd jobs, among them pumping gas. Meanwhile he was fitted for dentures and worked on his embouchure. Three months later he got a gig in New York. Between 1966 and 1974, Baker mostly played flugelhorn and recorded music that could mostly be classified as West Coast jazz.

After developing a new embouchure resulting from dentures, Baker returned to the straight-ahead jazz that began his career. He relocated to New York City and began performing and recording again, including with guitarist Jim Hall. Later in the 1970s, Baker returned to Europe, where he was assisted by his friend Diane Vavra, who took care of his personal needs and otherwise helped him during his recording and performance dates. From 1978 until his death in 1988, Baker resided and played almost exclusively in Europe, returning to the US roughly once a year for a few performances. This was Baker’s most prolific era as a recording artist. However, as his extensive output is strewn across numerous, mostly small European labels, none of these recordings ever reached a wider audience, even though many of them were well received by critics, who maintain that the period was one of Baker’s most mature and rewarding. Of particular importance are Baker’s quartet featuring the pianist Phil Markowitz (1978–80) and his trio with guitarist Philip Catherine and bassist Jean-Louis Rassinfosse (1983–85). He also toured with saxophonist Stan Getz during this period.  In 1983, British singer Elvis Costello, a longtime fan of Baker, hired the trumpeter to play a solo on his song “Shipbuilding”, from the album Punch the Clock. The song exposed Baker’s music to a new audience. Later, Baker often featured Costello’s song “Almost Blue” (inspired by Baker’s version of “The Thrill Has Gone”) in his concert sets, and recorded the song for Let’s Get Lost, a documentary film about his life.  The video material recorded by Japanese television during Baker’s 1987 tour in Japan showed a man whose face looked much older than he was, but his trumpet playing was alert, lively and inspired. Baker recorded the live album Chet Baker in Tokyo with his quartet featuring pianist Harold Danko, bassist Hein van de Geyn and drummer John Engels less than a year before his death, and it was released posthumously. Silent Night, a recording of Christmas music, was recorded with Christopher Mason in New Orleans in 1986 and released in 1987.

At about 3:10 am on May 13, 1988, Baker was found dead on the Prins Hendrikkade, near the Zeedijk, the street below his second-story room of Hotel Prins Hendrik in Amsterdam, the Netherlands, with serious wounds to his head. Heroin and cocaine were found in his hotel room, and an autopsy also found these drugs in his body. There was no evidence of a struggle, and the death was ruled an accident. A plaque outside the hotel memorializes him and the room he was staying in, No. 210, is named “The Chet Baker Room”.  Baker is buried at the Inglewood Park Cemetery in Inglewood, California.