Grant was born in Idabel, Oklahoma. Though he would be known later for his keyboards and vocals, Grant also played trumpet and drums. Grant attended four music schools, eventually becoming a music teacher. He augmented his income by performing in clubs during his army service, throughout which he was stationed in Fort Bliss, Texas. Grant signed with Decca Records in 1957 and his first single "The End" reached number 7 on the Billboard Hot 100chart. The single "Ebb Tide" sold over one million copies, gaining gold disc status. He recorded five more singles that made the charts, including "Swingin' Gently" (from Beyond the Reef), and six additional albums (mostly on the Decca label) through 1968. He also recorded the album Yes Sirree and the instrumental album Trade Winds, single-tracked on the Hammond organ and piano, featuring the love theme from the film El Cid and Chaplin's "Eternally". This album featured some realistic-sounding "tropical bird calls" produced by his electric organ. "House of Bamboo" was another big-selling single. In all, Grant recorded 30 albums for Decca, mostly on the Brunswick label, a subsidiary of Decca.