Dr. Ken alum Albert Tsai, who guest-starred in the 9JKL pilot, has been promoted to series regular opposite Mark Feuerstein for the first season of CBS’ family comedy.

9JKL is inspired by a time in Feuerstein’s adult life when he lived in apartment 9K in the building he grew up in, sandwiched between his doting parents’ apartment, 9J, and his brother, sister-in-law and their baby’s apartment, 9L, and his attempts to set boundaries with his intrusive but well-meaning family.

Tsai plays Ian, a precocious cinephile who is unimpressed with Josh’s (Feuerstein) TV career. Very smart, sophisticated, mature and outspoken, Ian is a latchkey kid who hangs out in the lobby because his single mom is always at work. In many ways, he is more grown up than Josh.

Tsai, who played Dave on Dr. Ken, earned a best supporting actor Critics’ Choice Award nomination in 2014 for his breakout role on Trophy Wife. He recurred on ABC’s Fresh Off the Boat and recently guest-starred on Crazy Ex-Girlfriend and The Mr. Peabody & Sherman Show. He’s repped by Coast to Coast Talent, Treadwell Entertainment Group and attorney Steve Younger.