Sajin made his big screen debut in 2015 with
Mumbai Taxi where he played a minor role. He then played another minor role in the film
Thilothama . Gopu's role of the jeep driver in
Lijo Jose Pellissery's
Churuli in 2021 became a turning point in his career. The same year he played the character of Saji Vypin in
Jan.E.Man, where his performance was acclaimed. In 2023, he starred in one of the lead roles in the horror-comedy
Romancham and his character Niroop was well received by the audience. Sajin received much critical praise for his role as Ambaan in
Jithu Madhavan's gangster action comedy
Aavesham. Vignesh Madhu of
The New Indian Express wrote, "Ranga's right-hand man is Ambadi, who he fondly—and funnily—calls Ambaan. It is an equally caricaturish role with the might of a beast and the heart of a baby. Sajin Gopu, in this role, is a ball of fire and perfectly complements
Fahadh’s madness. These two characters ignite the film everytime it seems to run out of steam." == Filmography ==