Glenn Franklin Howerton III was born in Japan, the son of a decorated fighter pilot. The future star grew up in various parts of the world, including England and South Korea, before his family settled in Montgomery, AL. Howerton studied at Jefferson Davis High School in Montgomery before transferring to New World School of the Arts in Miami, FL. He went on to eventually graduate from the prestigious Juilliard School in New York with a BFA in the Actor Training Program, and worked during summer breaks as a drama teacher at French Woods Festival of the Performing Arts in Hancock, NY.Howerton made his onscreen acting debut portraying NBC Sports executive Dick Ebersol, in the made-for-television movie, "Monday Night Mayhem" (TNT, 2002). That same year, he starred in the short-lived "That '80s Show" (Fox, 2002) as Corey Howard, a struggling musician and record store clerk from Southern California. The series was a spin-off of the hit comedy "That '70s Show" (Fox, 1998-2006), where Corey's cousin Eric (Topher Grace) was the central character. Even though both shows had a similar structure and featured an up-and-coming cast, "That ''80s Show" suffered from low ratings and comparisons to its predecessor before being yanked after one season.Following the cancellation, Howerton was cast in a guest-starring role on the medical drama "ER," playing a second-year resident at Chicago's fictional County General Hospital. The actor made his feature film debut in the 2005 romantic comedy "Must Love Dogs," opposite Diane Lane and John Cusack. Despite essaying smaller roles, Howerton's film appearances showcased his range as an actor - from playing a doctor in the action thriller "Crank" (2006), to portraying the son of a dying woman (Sally Field) in the family drama "Two Weeks" (2006), to falling prey to three masked serial killers in the horror film "The Strangers" (2008). However, it was the small screen that provided Howerton with the role of a lifetime. In 2005, the actor starred in "It's Always Sunny in Philadelphia," a comedy series he created and developed with Charlie Day and Rob McElhenney; both of whom also starred on the show. The series followed a group of friends living in South Philadelphia who owned a run-down bar called Paddy's Pub. Howerton played Dennis Reynolds, a narcissistic Ivy Leaguer with a twin sister (Kaitlin Olson) and an exploitative, overbearing father (Danny DeVito). His co-creators Day and McElhenney played the childhood friends of Howerton's character. "It's Always Sunny in Philadelphia" gained a strong cult following for its blue-collar wit, talented cast, and critical comparisons to shows like "Seinfeld" (NBC, 1990-98) and "Cheers" (NBC, 1982-1993). The addition of DeVito to the cast in the second season also helped boost the show's ratings. Howerton also worked behind the scenes, serving as the show's producer and writing several episodes. In 2009, the actor showcased his voiceover talent for "The Cleveland Show" (Fox, 2009-13), an animated series created by "Family Guy" (Fox, 1999-) creator Seth MacFarlane.