The prize would also normally would make Ben a near certainty to win best director at the Oscars later this month, since the Directors Guild recipient nearly always goes on to claim the same prize at Hollywood's biggest night.
But Ben surprisingly missed out on an Oscar directing nomination, along with several other key favourites, including fellow Directors Guild contenders Kathryn Bigelow for Zero Dark Thirty and Tom Hooper for Les Miserables.
Ben's Oscar snub has not hurt Argo and may even have earned it some favour among awards voters as an underdog favourite. Argo has dominated other awards since the Oscar nominations.
"I don't think that this makes me a real director, but I think it means I'm on my way," said Ben, who won for just his third film behind the camera.
Backstage at the Directors Guild honors, Ben said he had nothing but respect for the academy and that "you're not entitled to anything".
Milos Forman, a two-time Directors Guild and Oscar winner for One Flew Over the Cuckoo's Nest and Amadeus, received the group's lifetime-achievement award. Guild President Taylor Hackford let the crowd in a toast to Milos, who was ill and unable to attend.