He went on to be described as the "best impresario in the world" by singer Harry Belafonte, one of many artists whose concerts he produced in Montreal and elsewhere during a more than fifty-year career. Other acts included Nana Mouskouri, Joan Baez, Danny Kaye, Glenn Gould, Liberace, Janis Joplin, Maureen Forrester, Isaac Stern, The Band, Gordon Lightfoot, the Peking Opera, Monty Python's Flying Circus, the New York Philharmonic orchestra as well as Broadway musicals. Gesser also co-founded Les Feux Follets, a French-Canadian folk dance company in 1955. Gesser headed the entertainment for the Canadian pavilion at Montreal's Expo 67 world fair in 1967, presenting more than 400 shows. He repeated his role at the Osaka World Fair in Osaka, introducing many unknown Canadian artists to an international audience.