Through all his riverboat experience Armstrong’s musicianship began to mature and expand. At twenty, he could read music and he started to be featured in extended trumpet solos, one of the first jazzmen to do this, injecting his own personality and style into his solo turns. He had learned how to create a unique sound and also started using singing and patter in his performances. In 1922, Armstrong joined the exodus to Chicago, where he had been invited by his mentor, Joe "King" Oliver, to join his Creole Jazz Band and where he could make a sufficient income so that he no longer needed to supplement his music with day labor jobs. It was a boom time in Chicago and though race relations were poor, the “Windy City” was teeming with jobs for black people, who were making good wages in factories and had plenty to spend on entertainment.
Oliver's band was the best and most influential hot jazz band in Chicago in the early 1920s, at a time when Chicago was the center of the jazz universe. Armstrong lived like a king in Chicago, in his own apartment with his own private bath (his first). Excited as he was to be in Chicago, he began his career-long pastime of writing nostalgic letters to friends in New Orleans. As Armstrong’s reputation grew, he was challenged to “cutting contests” by hornmen trying to displace the new phenom, who could blow two hundred high C’s in a row. Armstrong made his first recordings on the Gennett and Okeh labels (jazz records were starting to boom across the country), including taking some solos and breaks, while playing second cornet in Oliver's band in 1923. At this time, he met Hoagy Carmichael (with whom he would collaborate later) who was introduced by friend Bix Beiderbecke, who now had his own Chicago band.
Armstrong enjoyed working with Oliver, but Louis' second wife, pianist Lil Hardin Armstrong, urged him to seek more prominent billing and develop his newer style away from the influence of Oliver. Armstrong took the advice of his wife and left Oliver's band. For a year Armstrong played in Fletcher Henderson's band in New York on many recordings. After playing in New York, Armstrong returned to Chicago, playing in large orchestras; there he created his most important early recordings. Lil had her husband play classical music in church concerts to broaden his skill and improve his solo play and she prodded him into wearing more stylish attire to make him look sharp and to better offset his growing girth. Lil’s influence eventually undermined Armstrong’s relationship with his mentor, especially concerning his salary and additional moneys that Oliver held back from Armstrong and other band members. Armstrong and Oliver parted amicably in 1924. Shortly afterward, Armstrong received an invitation to go to New York City to play with the Fletcher Henderson Orchestra, the top African-American band of the day. Armstrong switched to the trumpet to blend in better with the other musicians in his section. His influence upon Henderson's tenor sax soloist, Coleman Hawkins, can be judged by listening to the records made by the band during this period.
During that time he also did dozens of recording sessions with numerous Blues singers, including Bessie Smith's 1925 classic recording of "St. Louis Blues". He also recorded with Clarence Williams and the Red Onion Jazz Babies. In 1925 Armstrong moved back to Chicago and joined his wife's band at the Dreamland Cafe (3520 South State Street). He also played in Erskine Tate's Vendome Orchestra and then with Carrol Dickenson's Orchestra at the Sunset Cafe (313-17 East 35th Street at the corner of Calmet Street). Armstrong recorded his first Hot Five records that same year. This was the first time that Armstrong had made records under his own name. The records made by Louis Armstrong's Hot Five and Hot Seven are considered to be absolute jazz classics and speak of Armstrong's creative powers. The band never played live, but continued recording until 1928. While working at the Sunset, Louis met his future manager, Joe Glaser. Glaser managed the Sunset at that time. Armstrong continued to play in Carrol Dickenson's Orchestra until 1929.
He also led his own band on the same venue under the name of Louis Armstrong and his Stompers. For the next two years Armstrong played with Carroll Dickerson's Savoy Orchestra and with Clarence Jones' Orchestra in Chicago. By 1929 Louis was becoming a very big star. He toured with the show "Hot Chocolates" and appeared occasionally with the Luis Russell Orchestra, with Dave Peyton, and with Fletcher Henderson. Armstrong moved to Los Angeles in 1930 where he fronted a band called Louis Armstrong and his Sebastian New Cotton Club Orchestra.
In 1931 he returned to Chicago and assembled his own band for touring purposes. In June of that year he returned to New Orleans for the first time since he left in 1922 to join King Oliver's Creole Jazz Band. Armstrong was greeted as a hero, but racism marred his return when a White radio announcer refused to mention Armstrong on the air and a free concert that Louis was going to give to the cities' African-American population was cancelled at the last minute. Louis and Lil also separated in 1931. In 1932 he returned to California, before leaving for England where he was a great success.
For the next three years Armstrong was almost always on the road. He crisscrossed the U.S. dozens of times and returned to Europe playing in Denmark, Sweden, Norway, Holland and England. In 1935 he returned to the U.S. and hired Joe Glaser to be his manager. He had known Glaser when he was the manager of the Sunset Cafe in Chicago in the 1920s. Glaser was allegedly connected to the Al Capone mob, but proved to be a great manager and friend for Louis. Glaser remained Armstrong's manager until his death in 1969. Glaser took care of the business end of things, leaving Armstrong free to concentrate on his music. He also hired the Luis Russell Orchestra as Louis' backup band with Russell as the musical director. This was like going home for Armstrong, because Russell's Orchestra was made up of predominantly New Orleans musicians, many of whom had also played with King Oliver. The band was renamed Louis Armstrong and his Orchestra and was one of the most popular acts of the Swing era. Glaser put the band to work and they toured constantly for the next ten years. During this period Armstrong became one of the most famous men in America.