Jeong worked as a doctor before becoming a successful actor.
"I was definitely a late bloomer, and I didn't know where I was going to go with this," Jeong told Business Insider in 2019 about his transition to acting. "All I knew was I just had a deep, deep love of performing. I felt like I had an aptitude for it, but more importantly, I had a passion for it."
Best known for his role as Mr. Chow in "The Hangover," his own sitcom "Dr. Ken," and as a judge on "The Masked Singer," Jeong studied pre-med at Duke University, got his MD at UNC Chapel Hill, then completed his residency in New Orleans.
According to The Washington Post, "he treated patients at an HMO clinic [during the day]; at night, he scooped up as many stand-up gigs as he could." His big break came when Judd Apatow cast him as the OB in "Knocked Up."