Educated at Operastudio 67 and University College of Opera in Stockholm, Sweden.
As a student he sang Ceprano in Rigoletto at the Royal Opera in Stockholm, Michele in Il Tabarro, Nick Shadow in Rakes Progress, Renato in Ballo in Maschera and the title role in Rigoletto.
Kosma made his professional debut as Monterone in Rigoletto at the opera in Malmö 2004. He stayed there the following season singing roles in Turandot, Faust and Life with an Idiot by Schnittke.
The following season he sang Masetto in Don Giovanni at Värmlandsoperan and the Innkeeper and Captain of the Navy at Royal Opera in Stockholm.
He then sang the title role in Mefistofele by Boito with Södertäljeoperan in Stockholm and Oxenstierna in Cristina di Svecia by Foroni for Vadstena Academy, broadcast on radio in Sweden and Europe. The fall 2007 Kosma sang Barnaba in La Gioconda again with Södertäljeoperan.
Kosma was one of the finalists in Belvedere Vocal Competition in Vienna 2007.
Future engagements are Björn Olsson in The Poet and the Prophetess at Norrlandsoperan in spring 2008 and Oxenstierna in Cristina di Svecia this time at Confidencen in Stockholm.
