Jeong won the Big Easy Laff-Off in 1995 while still in residency. NBC president Brandon Tartikoff and The Improv founder Budd Friedman were judges and they both urged Jeong to move to Los Angeles. 1998–2006: Physician/comedian Jeong moved to Los Angeles in 1998 and practiced medicine for several years as a physician of internal medicine at a Kaiser Permanente hospital in Woodland Hills. He began performing regularly at The Improv and Laugh Factory comedy clubs. His stand-up work led to several television appearances, including NBC's The Office, FOX's MADtv, HBO's Entourage, and Curb Your Enthusiasm. In 2002, Jeong landed a spot on Comedy Central's Comic Groove. Jeong was also on Kims of Comedy. He made his film debut in Judd Apatow's Knocked Up as Dr. Kuni, which proved to be his breakout performance. From that point forward he was able to transition from medicine into a full-time career in the entertainment industry. Jeong gave up the practice in 2006 in favor of his acting career; however, he maintains his medical license and has assisted with medical emergencies during performances and on-set. 2006–present: Full-time entertainer Early in Jeong's career, he studied with director Natalia Lazarus at the Los Angeles Performing Arts Conservatory where she coached him for his film debut in Knocked Up. Lazarus coached Jeong from 2006 - 2012 for all of his film and television roles through The Hangover Part II. Subsequently, he has appeared in Step Brothers; Pineapple Express; Role Models as King Argotron; All About Steve; The Goods: Live Hard, Sell Hard; Couples Retreat; and as Mr. Chow in The Hangover, The Hangover Part II, and The Hangover Part III. He co-starred in Zookeeper, Transformers: Dark of the Moon, and Crazy Rich Asians. Jeong played Señor Chang on the NBC sitcom Community and was nominated for the show's "Male Breakout Star" at the 2010 Teen Choice Awards. He was nominated for two 2010 MTV Movie Awards, winning the award for Best WTF Moment and for MTV Movie Award for Best Villain for The Hangover. In fall 2010, Adidas basketball began a wide-ranging marketing campaign in which he starred as "Slim Chin", alongside NBA stars Dwight Howard and Derrick Rose. On May 22, 2011, he hosted the 2011 Billboard Music Awards in Las Vegas on ABC and was featured in a Hands Only CPR PSA campaign from the American Heart Association on June 15, 2011. In 2012, it