A substantial inheritance from his father allowed Sels to amass a 10,000 records, but a bombing during Second World War destroyed it.

On trumpet: Paul Heyndrickx, Charlie Knegtel, Theo Mertens, Herman and Nick Sandy Fissette; on trombone: Nat Peck, Frans Van Dijk, Jan Mertens and Christian Kellens; on Sax: Jay Cameron, Marcel Peeters, Gene Verstrepen, Bobby Jaspar and Roger Asselberghs plus Jean Warland on bass, Francis Coppieters on piano, John Ward on drums, Rudy Frankel on conga and Vilez Bill on bongo drum.

In 1951, he formed a band with 15 musicians, modelled after his idol Miles Davis, and later a still smaller group with which he toured in Germany.

In 1955, he composed the soundtrack for the movie Meeuwen Sterven in de Haven (Seagulls Die in the Harbour) by Roland Verhavert.

Although Jack Sels played with jazz legends like Dizzy Gillespie, Lester Young, Lou Bennett and Kenny Clarke, his decision to remain in Antwerp limited his international fame.