Born Jonathan Daniel Hamm to Daniel and Deborah Hamm on March 10, 1971, in St. Louis. His parents divorced when he was 2 years old, and he lived with his mother until she died when he was 10. Jon then lived with his father until he passed away when Jon was 20.
He appeared in small roles on TV shows until Clint Eastwood cast him in 1990's Space Cowboys. In 1991, he appeared in the highly regarded indie Kissing Jessica Stein, with was co-written and co-produced by Jennifer Westfeldt, who would go on to play an important role in Jobn's life.
In July of 2007, Jon debuted in his signature role as 1960s advertising man Don Draper on AMC's Mad Men.
- Space Cowboys (1990)
- Kissing Jessica Stein (1991)
- Stolen (2010)
- The Town (2010)
- Sucker Punch (2011)
- Bridesmaids (2011)
- Hosted Saturday Night Live on Oct. 25, 2008, Jan. 30, 2010 and Oct. 30, 2010.
- Recurring role on 30 Rock as Drew Baird.
- Guest voice as FBI director on The Simpsons on Dec. 12, 2010.
- Co-producer, Friends With Kids (2011)
Since 1997, Jon has been in a committed relationship with screenwriter/actress Jennifer Westfeldt.
- Jon became interested in acting in the first grade, when he was selected to play Winnie-the-Pooh.
- Jon's prom date was Sarah Clarke, who went on to TV fame on 24 and to appear in the Twilight series.
- Received a scholarship to study acting at the University of Missouri.
- Jon is such a fan of the St. Louis Cardinals baseball team that he narrated the squad's official 2011 World Series film.
- Fan of the NHL's St. Louis Blues.
- Loves to play golf.
- Stands 6 feet tall
- Adopted a rescue dog named Cora.
- When his character is required to smoke on Mad Men, Jon puffs herbal cigarettes that contain no tobacco.