Bartz graduated from the Baltimore City College high school and the Juilliard School; his break into the music industry came when filling in with Art Blakey's band at his father's club in Baltimore.
Bartz has played with Miles Davis, Charles Mingus, Max Roach, McCoy Tyner, and Jackie McLean. His group, the Ntu Troop, combined soul, funk, African music, hard bop, and avant-garde jazz.
In liner notes to his album released in 1995, The Red and Orange Poems, Bartz was described by jazz critic Stanley Crouch as "one of the very best who has ever picked up the instrument". He has recorded more than 40 solo albums and over 200 as a guest artist. He won a Grammy Award in 2005 for his playing on McCoy Tyner's album Illuminations.
Bartz was awarded the BNY Mellon Jazz 2015 Living Legacy Award, presented at a special ceremony at The Kennedy Center. He currently teaches at the Oberlin Conservatory of Music in Ohio, when not touring.