He is known best for his portrayals of Ray Butani on Schitt's Creek, Tick Pickwick on The Magicians, Rajiv Gidwani in the NBC sitcom Outsourced, and Jamil in the DC Extended Universe (DCEU) television series Peacemaker (2022–present).

[9] During the early years of Manji's career, he played small parts in various films and television shows, with recurring roles in Privileged, Better Off Ted and 24.

He initially auditioned for the role of Gupta;[1] Parvesh Cheena got the part, but the producers cast Manji as the scheming assistant manager Rajiv.

[10][11] Manji played Ray Butani on the CBC comedy Schitt's Creek from 2015 to 2020, for which he was nominated for a Canadian Screen Award.

In 2019, he starred in the NBC comedy Perfect Harmony as Reverend Jax, a missionary who runs a church.