He is best known for detailed period movies such as the Anne of Green Gables series of films, his movie adaptation of Timothy Findley's novel The Piano Man's Daughter, feature films and TV-movies such as Under the Piano, Butterbox Babies, Sleeping Dogs Lie and the CBS mini-series Seasons of Love, as well as long-running television series such as Road to Avonlea and Wind at My Back.

[1] His first foray into film-making was with a half-hour Hans Christian Andersen Christmas special, titled The Fir Tree (1979), of which he edited and also had a small acting role.

[2] From there Sullivan wrote, produced and directed Krieghoff (1979), a widely acclaimed docu-drama in French and English on the life of the prominent German artist and illustrator of 19th century Quebec.

[citation needed] In 1980 Sullivan wrote, produced, and directed Megan Carey (1980), a film about a young Irish immigrant indentured on a farm in 19th century Canada.

His first feature film was The Wild Pony (1982), which he co-wrote, co-produced and directed, it became a turning point for Sullivan, having been the first feature-length movie to be made exclusively for pay-TV in Canada.

Part of Anne of Green Gables' immense attraction was its rich look, featuring painstakingly recreated sets and detailed costumes that imbued it with a magical reality.

However Montgomery's heirs had been told two shows based on works Sullivan believed it had acquired dramatic rights to, had failed to turn a profit, so they sued.

Sullivan counter-sued, for damage to his reputation, successfully providing evidence that the heirs of Montgomery had no reversionary copyright claims to the dramatic rights to the original novel they had sold him.

[17][circular reference] Sullivan is currently writing and producing an adaptation of Timothy Findley's Famous Last Words about the plot to kidnap the Duke and Duchess of Windsor in Lisbon in 1936, known as Operation Willi.

Out of the Shadows closely follows the scientific journey of a group of material physicists and art historians during the attribution of Rembrandt's painting Old Man with a Beard at the Brookhaven National Synchrotron in Long Island, New York.