Ryan Fecteau easily won the Democratic primary for House District 11 in Biddeford.
The seat is being vacated by Democratic Rep. Paulette Beaudoin, who cannot run again because of term limits.
David Flood, a magazine publisher and former city councilor who is active in downtown redevelopment, ran against Fecteau, a Biddeford native who helped run marriage equality campaigns while attending college.
Fecteau finished with 493 votes, while Flood had 263. More than 12 percent of Biddeford’s 13,500 registered voters cast a ballot.
Fecteau will run against Republican Debi Davis in November.
Fecteau, 21, became involved in local politics as a high school representative to the school board.
In 2011, he was a York County field organizer for Equality Maine; the following year he was rehired as a field organizer for Mainers United for Marriage.