Together with his brother Melvin Parker on drums Maceo joined James Brown in 1964. Maceo started playing baritone saxophone but soon switched to tenor. His powerful playing on 'Papa's Got A Brand New Bag', 'I Got You (I Feel Good)', 'Cold Sweat' and 'Say It Loud (I'm Black and I'm Proud)' quickly became a trademark of the new James Brown Funk sound during the mid-sixties. During live concerts James would introduce Maceo's explosive sax solos by shouting his famous phrase 'Maceo! Blow Your Horn!'. In the late sixties the horn section formed around Maceo Parker on tenor, St. Clair Pickney on baritone, Alfred 'Pee Wee' Ellis on alto, Fred Wesley on trombone and Richard 'Kush' Griffith on trumpet were as much a part of James Brown's success as the rhythm section formed around the funky drummers Melvin Parker and later Clyde Stubblefield.
After the split with James Brown in 1969 Maceo took his brother Melvin and guitarist Jimmy Nolan to form his own Funk band, Maceo & All The King's Men.