Representative Charles A. ­Murphy, one of Beacon Hill’s most powerful figures before he was ousted by the Democratic leadership in a power struggle, said Friday that he will resign from the House effective at the end of July.

Murphy, a 46-year-old former Marine from Burlington, has served in the House since 1997. His departure follows that of James E. Vallee, who left the House this month, having also served in a leadership role.