 Following graduation from McGill, he founded Vivafilm which imported and distributed foreign films across Canada.He later started a production company, RSL Entertainment, which produced fifteen films, most notably George Kaczender's "In Praise of Older Women" and Ted Kotcheff's "Joshua Then and Now".Lantos co-founded the Canadian film and television company Alliance Communications Corporation with partners Victory Loewy, John Kemeny, Stephen J. Roth, and Denis Héroux.