Langley reached for the tour by finishing 17th in the qualifying tournament late last year and he made a shocking debut with a bogey-free round at the Waialae Country Club.
His day was highlighted by a 56-foot eagle putt at the par-5 ninth hole and he finished his round off with a six-foot birdie effort at the 18th as the sun was setting.
He owned a one-shot lead over fellow-rookie Russell Henley, with whom he was paired for the first round. Henley earned his exempt status this year by finishing third on the money list of the Web.com Tour in 2012.
Tied for third at 64 were Tim Clark and Scott Piercy, who finished 13th last week at the season-opening Tournament of Champions.
Langley, 23, turned pro in 2011 after playing his college golf at the University of Illinois. He qualified for last year's U.S. Open, where he finished tied for 29th.