Newborn came from a musical family: his father, Phineas Newborn Sr., was a drummer in blues bands,and his younger brother, Calvin, a jazz guitarist. Phineas was born in Whiteville, Tennessee.He studied piano as well as trumpet, and tenor and baritone saxophone. 　　Before moving on to work with Lionel Hampton, Charles Mingus, and others, Newborn first played in an R&B band led by his father on drums, with his brother Calvin on guitar, Tuff Green on bass, Ben Branch and future Hi Records star Willie Mitchell. The group was the house band at the now famous Plantation Inn Club in West Memphis, Arkansas, from 1947 to 1951, and recorded as B. B. King's band on his first recordings in 1949, as well as the Sun Records sessions in 1950.They left West Memphis in 1951 to tour with Jackie Brenston as the "Delta Cats" in support of the record "Rocket 88", recorded by Sam Phillips and considered by many to be the first ever rock & roll record (it was the first Billboard No. 1 record for Chess Records). 　　Among his earliest recordings, from the early 1950s, are those for Sun Records with blues harmonica player Big Walter Horton,[8] We Three (as a trio with drummer Roy Haynes and bassist Paul Chambers), and his debut as a solo artist on RCA Victor, Phineas' Rainbow. 　　From 1956, Newborn began to perform in New York City, making his first album as a leader in that year. His trios and quartets at that time included Oscar Pettiford, Kenny Clarke, George Joyner and Philly Joe Jones.[9] Newborn created enough interest internationally to work as a solo pianist in Stockholm in 1958 and in Rome the following year. 　　On March 16, 1960, 29-year-old Newborn replaced Thelonious Monk and performed "It's Alright with Me" on the ABC-TV series Music for a Spring Night. Newborn moved to Los Angeles that year, and recorded a sequence of piano trio albums for the Contemporary label. However, some critics found his playing style rather facile, and Newborn developed emotional problems as a result, necessitating his admission to the Camarillo State Mental Hospital for some periods. He also suffered a hand injury which hindered his playing. 　　Newborn's later career was intermittent due to ongoing health problems. This is most true of the period from the mid-1960s to mid-1970s when he faded from view, underappreciated and underrecorded. He made a partial comeback in the late 1970s and early 1980s, although this return apparently failed to benefit his financial situation. He died in 1989 after the discovery of a growth on his lungs and was buried in Memphis National Cemetery.