Jeannin has appeared in over forty plays, and numerous film and television projects, among them Affiction, Grey Owl, and 300. He has performed in some of Canada's finest theatres, notably the Stratford Festival, the National Arts Centre, Regina's Globe Theatre and the Centaur Theatre in Montreal. A sought-after workshop participant, he has assisted in the development of over 100 plays, and lends his voice to various cartoon series, such as Mona the Vampire, Arthur and Postcards from Buster.