Derek Scully and Outspan Foster

Two friends, bassist Derek Scully and guitarist Outspan Foster, form the band at the beginning of the novel.

Jimmy Rabbitte

Jimmy Rabbitte is the band's manager and the primary protagonist. He chooses the band's name, The Commitments; he dictates their musical direction, which is soul; and he begins recruiting and choosing new members and booking gigs.

Joey "The Lips" Fagan

Joey "The Lips" Fagan is a trumpet player. He is much older than the rest of the band. He claims to have formerly played with a number of leading soul bands. He is also a ladies' man, pursuing both of the band's female backup singers.

Steven James Clifford

Steven James Clifford is the band's piano player, an organist for the local church, and a reserved, intellectual medical student.

Imelda Quirke and Natalie Murphy

Imelda Quirke and Natalie Murphy are the backing vocalists, both chosen for sex appeal. They both have flings with Joey Fagan.

Mickah Wallace

Mickah Wallace is initially the band's brawling bouncer and roadie. He then becomes the band's second drummer and, finally, a crazed solo metal and punk rock vocalist.

Dean Fay

Dean Fay, originally a hesitant player tutored by Fagan, is the saxophonist and, eventually, a pretentious jazz fan.

Billy Mooney

Billy Mooney is the first drummer. He quits because he can't stand the band's singer, Deco.

Declan "Deco" Cuffe

Declan "Deco" Cuffe is the band's lead vocalist. He is crude, egotistical, and the source of most conflicts within the band.

The Overall Band Dynamic

The band are initially poor players, timid and hesitant at gigs. Over time they become better players and stage performers, but also increasingly come into conflict. Deco's ego, demands for attention, and obnoxiousness alienate the rest of the band. The backup singers fight over Fagan's attentions. The horn players argue over solos. Many of the band members turn against Jimmy's management and failure to secure their pay and larger gigs. Finally the band breaks up, just as there are signs of possible success.