He starred in Academy Award winning movies including Karakter by Mike van Diem and Antonia and the Oscar-nominated social drama Daens.

More recently he turned down roles in Stanley Kubrick's Eyes Wide Shut (due to commitments to other projects) and the James Bond film The World Is Not Enough.

"[4] For several years he also led the Studio Herman Teirnlick where he brought in many new teachers: actors from various theater companies (e.g., de Blauwe Maandag Compagnie, STAN, etc.).

In 2008 he was awarded the best actor prize at the Tiburon International Film Festival for his role in Man zkt vrouw (A Perfect Match).

[6] The movie Karakter in which Decleir played the leading role, won the Academy Award for best international feature film in 1997.