In the early 1940s Tristano played tenor saxophone and piano for a variety of engagements, including in a rumba band.
He began giving private music lessons at around the same time, including to saxophonist Lee Konitz.
From 1943 Tristano also taught at the Axel Christensen School of Popular Music.
He first received press coverage for his piano playing in early 1944, appearing in Metronome's summary of music in Chicago from that year, and then in Down Beat from 1945.
He recorded with some musicians from Woody Herman's band in 1945; Tristano's playing on these tracks "is characterized by his extended harmonies, fast single-line runs, and block chords."
He also recorded solo piano pieces in the same year.
Tristano also married in 1945; his wife was Judy Moore, a musician who sang to his piano accompaniment in Chicago in the mid-1940s.

Tristano's interest in jazz inspired a move to New York City in 1946.
As a preliminary step to moving there, he stayed in Freeport, Long Island, where he played in a restaurant with Arnold Fishkin (bass) and Billy Bauer (guitar).
This trio, with an assortment of bassists replacing Fishkin, was recorded in 1946–47.
Reviewers at the time commented on the originality of the piano–guitar counterpoint and the trio's approach to harmony.
Gunther Schuller later described one of their recordings as "too far ahead of its time" in its harmonic freedom and rhythmic complexity.

Tristano met saxophonist Charlie Parker in 1947.
They played together in bands that included bebop musicians Dizzy Gillespie and Max Roach later that year for radio broadcasts.
The pianist reported that Parker enjoyed his playing, in part because it was different from what Parker was accustomed to and did not copy the saxophonist's style.
In 1948 Tristano played less often in clubs, and added Konitz and a drummer to his regular band, making it into a quintet.
This band recorded the first sides for the New Jazz label, which later became Prestige Records.
Later that year Warne Marsh, another saxophonist student of Tristano's, was added to the group.

Tristano's band had two recording sessions in 1949 that proved to be significant.
The sextet recorded original compositions, including his "Wow" and "Crosscurrent", that were based on familiar harmonies; reviewers commented on the linearity of the playing and its departure from bebop.
Without a drummer, the other musicians also recorded the first free improvisations by a group – "Intuition" and "Digression".
For these tracks, the sequence in which the musicians would join in the ensemble playing, and the approximate timing of those entrances, were planned, but nothing else – harmony, key, time signature, tempo, melody or rhythm – was prepared or set.
Instead, the five musicians were held together by contrapuntal interaction.
Both tracks were praised by critics, although their release was delayed – "Intuition" was released late in 1950, and "Digression" not until 1954.
Parker and composer Aaron Copland were also impressed.
Numerous other musicians of the time, however, thought Tristano's music too progressive and emotionally cold, and predicted that it would not be popular with the public.

The sextet struggled to find enough work, but did play at Birdland's opening night "A Journey Through Jazz", a subsequent five-week engagement at that club, and at various other venues in the north-east of the US late in 1949.
They performed free pieces in these concerts, as well as Bach fugues, but found it difficult over time to continue to play with the freedom that they had initially felt.
In the early 1940s Tristano played tenor saxophone and piano for a variety of engagements, including in a rumba band. He began giving private music lessons at around the same time, including to saxophonist Lee Konitz. From 1943 Tristano also taught at the Axel Christensen School of Popular Music. He first received press coverage for his piano playing in early 1944, appearing in Metronome's summary of music in Chicago from that year, and then in Down Beat from 1945. He recorded with some musicians from Woody Herman's band in 1945; Tristano's playing on these tracks "is characterized by his extended harmonies, fast single-line runs, and block chords." He also recorded solo piano pieces in the same year. Tristano also married in 1945; his wife was Judy Moore, a musician who sang to his piano accompaniment in Chicago in the mid-1940s.
Tristano's interest in jazz inspired a move to New York City in 1946. As a preliminary step to moving there, he stayed in Freeport, Long Island, where he played in a restaurant with Arnold Fishkin (bass) and Billy Bauer (guitar). This trio, with an assortment of bassists replacing Fishkin, was recorded in 1946–47. Reviewers at the time commented on the originality of the piano–guitar counterpoint and the trio's approach to harmony. Gunther Schuller later described one of their recordings as "too far ahead of its time" in its harmonic freedom and rhythmic complexity.
Tristano met saxophonist Charlie Parker in 1947. They played together in bands that included bebop musicians Dizzy Gillespie and Max Roach later that year for radio broadcasts. The pianist reported that Parker enjoyed his playing, in part because it was different from what Parker was accustomed to and did not copy the saxophonist's style. In 1948 Tristano played less often in clubs, and added Konitz and a drummer to his regular band, making it into a quintet. This band recorded the first sides for the New Jazz label, which later became Prestige Records. Later that year Warne Marsh, another saxophonist student of Tristano's, was added to the group.
Tristano's band had two recording sessions in 1949 that proved to be significant. The sextet recorded original compositions, including his "Wow" and "Crosscurrent", that were based on familiar harmonies; reviewers commented on the linearity of the playing and its departure from bebop. Without a drummer, the other musicians also recorded the first free improvisations by a group – "Intuition" and "Digression". For these tracks, the sequence in which the musicians would join in the ensemble playing, and the approximate timing of those entrances, were planned, but nothing else – harmony, key, time signature, tempo, melody or rhythm – was prepared or set. Instead, the five musicians were held together by contrapuntal interaction. Both tracks were praised by critics, although their release was delayed – "Intuition" was released late in 1950, and "Digression" not until 1954. Parker and composer Aaron Copland were also impressed. Numerous other musicians of the time, however, thought Tristano's music too progressive and emotionally cold, and predicted that it would not be popular with the public.
The sextet struggled to find enough work, but did play at Birdland's opening night "A Journey Through Jazz", a subsequent five-week engagement at that club, and at various other venues in the north-east of the US late in 1949. They performed free pieces in these concerts, as well as Bach fugues, but found it difficult over time to continue to play with the freedom that they had initially felt.
Lennie Tristano