Hamm discussed the decade he spent struggling in Hollywood in a panel discussion with The Hollywood Reporter this week.
"After testing for my seventh network in a pilot season... I was told by the head of the network that I would never be a television star," he recalled.
Hamm further explained that it was incredibly frustrating to repeatedly be passed over for roles prior to being cast as Don Draper in Mad Men.
He said: "[I lived in] LA for 10 years, not working, having no money and no prospects. The days were kind of great; it was the long nights staring at the ceiling waiting for the phone to ring.
"The uncertainty is always the difficult part, at least it has been for me,"
He has since won a Golden Globe and two SAG Awards for Mad Men.
Last month, it was announced that Hamm has signed up for his first leading film role in the sports drama Million Dollar Arm.