After leaving the Conservatory, he worked at the Théâtre Nanterre-Amandiers with Jean-Pierre Vincent.

[citation needed] In 1992 he played Christian Ribet, a friend of Guillaume de Tonquédec, in the film Tableau d'honneur (Honour Roll) by Charles Nemes.

In 2006, he played in the theater as Edward Bond, directed by Alain Francon, at the Avignon Festival and the Théâtre de la Colline in Paris.

In January 2008, he performed in a show at the Theatre Antoine in Paris for Yasmina Reza's God of Carnage.

[citation needed] Elmosnino was born in the Paris suburbs to a Sephardic Jewish (Moroccan-Jewish) father who was an industrial designer at Thomson CSF, and to an Alsatian mother who left EDF to raise her children.