stylistic:tone
1944–1948: New York City and the bebop years

In September 1944, Davis accepted his father's idea of studying at the Juilliard School of Music in New York City. After passing the audition, he attended classes in music theory, piano and dictation. Davis often skipped his classes.

Much of Davis's time was spent in clubs seeking his idol, Charlie Parker. According to Davis, Coleman Hawkins told him "finish your studies at Juilliard and forget Bird ". After finding Parker, he joined a cadre of regulars at Minton's and Monroe's in Harlem who held jam sessions every night. The other regulars included J. J. Johnson, Kenny Clarke, Thelonious Monk, Fats Navarro, and Freddie Webster. Davis reunited with Cawthon and their daughter when they moved to New York City. Parker became a roommate. Around this time Davis was paid an allowance of $40 (equivalent to $690 in 2023).

In mid-1945, Davis failed to register for the year's autumn term at Juilliard and dropped out after three semesters because he wanted to perform full-time. Years later he criticized Juilliard for concentrating too much on classical European and "white" repertoire, but he praised the school for teaching him music theory and improving his trumpet technique.

Davis began performing at clubs on 52nd Street with Coleman Hawkins and Eddie "Lockjaw" Davis. He recorded for the first time on April 24, 1945, when he entered the studio as a sideman for Herbie Fields 's band. During the next year, he recorded as a leader for the first time with the Miles Davis Sextet plus Earl Coleman and Ann Baker, one of the few times he accompanied a singer.

In 1945, Davis replaced Dizzy Gillespie in Charlie Parker's quintet. On November 26, he participated in several recording sessions as part of Parker's group Reboppers that also involved Gillespie and Max Roach, displaying hints of the style he would become known for. On Parker's tune " Now's the Time ", Davis played a solo that anticipated cool jazz. He next joined a big band led by Benny Carter, performing in St. Louis and remaining with the band in California. He again played with Parker and Gillespie. In Los Angeles, Parker had a nervous breakdown that put him in the hospital for several months. In March 1946, Davis played in studio sessions with Parker and began a collaboration with bassist Charles Mingus that summer. Cawthon gave birth to Davis's second child, Gregory, in East St. Louis before reuniting with Davis in New York City the following year. Davis noted that by this time, "I was still so much into the music that I was even ignoring Irene." He had also turned to alcohol and cocaine.

Davis was a member of Billy Eckstine's big band in 1946 and Gillespie's in 1947. He joined a quintet led by Parker that also included Max Roach. Together they performed live with Duke Jordan and Tommy Potter for much of the year, including several studio sessions. In one session that May, Davis wrote the tune "Cheryl", for his daughter. Davis's first session as a leader followed in August 1947, playing as the Miles Davis All Stars that included Parker, pianist John Lewis, and bassist Nelson Boyd; they recorded "Milestones", "Half Nelson", and "Sippin' at Bells". After touring Chicago and Detroit with Parker's quintet, Davis returned to New York City in March 1948 and joined the Jazz at the Philharmonic tour, which included a stop in St. Louis on April 30.