One of the most talented pianists of the 1940s, Johnny Guarnieri had the ability to closely imitate Fats Waller, Count Basie, and even Art Tatum. Not too surprisingly, he was in great demand during his prime years. Guarnieri started classical piano lessons when he was ten and soon switched to jazz. In 1939, he joined Benny Goodman's orchestra, recording frequently with both the big band and B.G.'s sextet. In 1940, Guarnieri became a member of Artie Shaw's orchestra and gained fame playing harpsichord on Shaw's popular Gramercy Five recordings. After further associations with Goodman (1941) and Shaw (1941-1942), he was with Tommy Dorsey (1942-1943) and then freelanced. Among Guarnieri's many recordings during this era were important dates with Lester Young ("Sometimes I'm Happy"), Roy Eldridge, Ben Webster, Coleman Hawkins, Rex Stewart, Don Byas, and Louis Armstrong ("Jack-Armstrong Blues"). He also recorded frequently as a leader during 1944-1947, including one date on which Lester Young was his sideman. Guarnieri joined the staff of NBC in the late '40s, appeared in the Coleman Hawkins/Roy Eldridge television pilot After Hours (1961), moved to California in the '60s where he often played solo piano, and a few times in the 1970s toured Europe. Guarnieri's later records often found him playfully performing stride in 5/4 time. He recorded as a leader through the years for such labels as Savoy, Majestic, Coral (1956), Golden Crest, Camden, Dot, Black & Blue, Dobre, and Taz-Jazz (1976 and 1978). ~ Scott Yanow, All Music Guide
In 1949 Guarnieri recorded an album with June Christy titled June Christy & The Johnny Guarnieri Quintet. Guarnieri has recorded with numerous artists, and in his later years he shifted more toward jazz education. In commemoration of his reputation as a teacher, Guarnieri's students financed a label for him called Taz Jazz Records. In the 1970s Guarnieri recorded numerous albums on his new label, and until 1982 worked "Tail of the Cock" nightclub in Studio City, California. He died onstage during a performance with Dick Sudhalter.