His first credits are as an assistant editor on two 1982 films directed by Sidney Lumet, Deathtrap and The Verdict. He went on to edit five of Lumet's films between 1984 and 1992. Mondshein was among the first film editors to adopt electronic techniques (on the film Power (Lumet-1986)).[4]
Mondshein has had a notable collaboration on eleven films with the Swedish director Lasse Hallström. Their collaboration commenced with Hallström's first English language film Once Around (1991). It includes Chocolat (2000), which was nominated for the Academy Award for Best Picture, and for which Mondshein was nominated for a second Eddie. Their most recent collaboration is The Hundred-Foot Journey (2014). Because of his concurrent work on The Sixth Sense, Mondshein played only a peripheral role in Hallström's The Cider House Rules (1999); Lisa Zeno Churgin edited that film, which was nominated for seven Academy Awards including Film Editing.[5]