An American actor, born Jonathan Daniel Hamm in St. Louis, Missouri, USA, in 1971. His mother died when he was ten years old, followed by his father ten years later. Jon received a scholarship to study acting at the University of Missouri and was working at the same time as a high school teacher, then he moved to Hollywood. He was married to actress Jennifer Westfeldt. Among his most notable works is the series Mad Men (2007-2015).