[5] By 1920, Stacy was playing piano in Peg Meyer's jazz ensemble at Cape Girardeau High School, the Bluebird Confectionary, and the Sweet Shop.

[6] By 1921, the band was known as Peg Meyer's Melody Kings and started touring the Mississippi River on the Majestic and other riverboats.

[7] In the early 1920s, Stacy moved to Chicago, where he performed with Paul Mares,[2] leader of the New Orleans Rhythm Kings, playing a genre of jazz which came to be called "Chicago-style".

[2] Stacy left Floyd Towne, moved to New York City, and spent 1935–39 with the Benny Goodman Orchestra, including the Carnegie Hall concert in 1938.

"At the Carnegie Hall concert, after the usual theatrics, Jess Stacy was allowed to solo and, given the venue, what followed was appropriate ... Used to just playing rhythm on the tune, he was unprepared for a turn in the spotlight, but what came out of his fingers was a graceful, impressionistic marvel with classical flourishes, yet still managed to swing.

It was the best thing he ever did, and it's ironic that such a layered, nuanced performance came at the end of such a chaotic, bombastic tune", wrote David Rickert.

[2] While playing at the piano bar in Leon's Steak House, he walked out after a drunken woman spilled beer in his lap.

[5] In addition to the Goodman and Crosby orchestras, Stacy played with Bix Beiderbecke, Eddie Condon, Bud Freeman, George Gershwin, Lionel Hampton, Billie Holiday, Gene Krupa, Jack Teagarden, and Horace Heidt.