[2] Mangelsdorff began his career as a professional musician in 1947 as a rhythm guitarist in the Otto Laufner Big Band, which played in US Army clubs.

[2] As the German representative for the Newport Jazz Festival International Band in 1958,[4] he collaborated with the American musicians Gerry Mulligan and Louis Armstrong.

[3] "He made solo trombone – a heretofore unknown concept in jazz – a reality via multiphonics, the physically and technically demanding simultaneous blowing and singing of notes into his horn; the method opened vast new dimensions like harmonies and chords".

[2] He performed with pianist Chick Corea, cool jazz saxophonist Lee Konitz and bassist Jaco Pastorius.

[4] Mangelsdorff later worked with the NDR Big Band, Old Friends (led by Manfred Schoof), the Globe Unity Orchestra, and the United Jazz + Rock Ensemble.

[1] In 2009, the Institut für Stadtgeschichte Frankfurt [de] founded a Jazzarchiv (jazz archive) with the takeover of Mangelsdorff's estate.