Born in Gries am Brenner, Tyrol, Moretti is the eldest of four brothers, including Thomas, Christoph and fellow actor Gregor Bloéb.

Since 1997, he has been married to Julia Moretti (née Wilhem), an oboist.

Moretti studied composition at the Vienna University of Music and Applied Arts, then went to Munich to train for the stage at the renowned Otto-Falckenberg-Schule.

After graduation he was a permanent member of the Bayerisches Staatsschauspiel ensemble (Frank Baumbauer) and played at the Munich Kammerspiele (Dieter Dorn) from 1985 to 1995 where he earned critical praise in a sweeping variety of productions, appearing in Bertolt Brecht's Man is Man, Achternbusch's Der Frosch (The Frog) and playing the lead in Shakespeare's Troilus and Cressida.

Moretti appeared in the TV series Inspector Rex from 1994 to 1998 as Richard Moser, the main policeman in the murder unit.