GORHAM, Maine — Harrison Richardson, a Portland lawyer, ex-legislator and one-time candidate for governor who played key roles in the enactment of the state income tax and landmark environmental legislation, has died at the age of 79.

Richardson, a leader of Republican party’s liberal wing during the late 1960s and early 70s, died Thursday at his home in Gorham following a debilitating stroke.

He was narrowly defeated in the 1974 gubernatorial primary by James Erwin, who went on to lose the general election to independent James Longley. Democrat George Mitchell finished second.

Richardson was a former trustees’ chairman at the University of Maine, where he played football. His wife, Catherine, died six months ago. His survivors include three children.