Powell -- best known for playing Toofer on the NBC comedy -- married Knox Saturday at Tribeca Rooftop after four years of dating, People magazine reported.
Knox wore a Rosa Clara gown while Powell donned a custom tux, the magazine said.
Powell proposed to Knox last summer during an elaborate picnic, which culminated with a fortune cookie that read "Jill Knox, will you marry me?"
At the conclusion of filming for the final season of "30 Rock," Powell predicted he'd be spending most of his time focusing on his upcoming nuptials.
"I have a feeling that most of my energy will be focused on my upcoming wedding," he told USA Today.