"The Celtic Soul Brothers" was the first song recorded and released by the revamped Dexys Midnight Runners' lineup, which added fiddle players Helen O'Hara, Steve Brennan and Roger MacDuff and bassist Giorgio Kilkenny. Reflecting the revised lineup, the song's instruments feature mandolins and violins rather than the horn fanfares featured in the group's earlier work. The song was inspired by 1960s soul music, and coauthor Billingham has stated that The Whispers' song "Needle in a Haystack" was a particular influence, accounting for "The Celtic Soul Brothers'" unusual melody. Coauthor and Dexys Midnight Runners' lead singer Rowland has stated that the song was about him and Dexys' trombone player Paterson; Rowland being Irish and Paterson being Scottish. Rowland also stated the song expresses his devotion to the band. Author Richard White calls the song "a stand aside, effervescent statement." Critic Ned Raggett of Allmusic referred to the song as a highlight of Too-Rye-Ay.Ira Robbins of Trouser Press refers to the song as "jolly, rollicking jug band fare." Author Simon Reynolds called the song "a manifesto of a single."Julie Burchill of New Musical Express remarked that although the song is intended to sound ethnically Celtic, it sounds more like a "Redcoat romp." Author Maury Dean claims that this song was an inspiration for Roddy Doyle's 1987 novel The Commitments, which was later made into a 1991 film by the same title.