2016 marked the year that Sully Seagull's extraordinary career started. He landed a substantial supporting role in The Shallows (2016), co-starring with Blake Lively in what was to become one of the most successful summer movies of the year. Sully received rave reviews for his multi-layered portrayal of a handicapped gull bravely trying to escape a scary shark's appetite. Vulture.com called him "The Breakout Movie Star of the Summer", and renowned film critic Winston Cook Wilson praised his "bold, controlled, and unexpected" performance and even demanded an Oscar nomination for the feathered star of Jaume Collet-Serra's thriller. Entertainment Weekly published an insightful article about the making of The Shallows (2016), pointing out: "Forget the shark that stalks Blake Lively; the seagull stranded with her on the rock [...] stealthily stole every scene he appeared in. Nicknamed Sully by the film's animal trainer, Katie Brock, the feathered star engaged comically with Lively's heroine Nancy and drew praise for his performance."

After a three-year hiatus from the spotlight, Sully was persuaded to take over a more demanding character role in Robert Eggers's Lighthouse (2019) with Robert Pattinson and Willem Dafoe. He agreed to appear uncredited in this acclaimed fantasy drama. The Lighthouse was Sully the Seagull's final on-screen appearance as a result of his death during an unexpectedly improvised scene alongside co-star Robert Pattinson.