The 26-year-old beat fellow Canadian and teammate Kate O'Brien 2-0 in the best-of-three-heats race.
The pair won the team event on Thursday and set a Pan Am record in the qualification races.
Sullivan added another gold on Friday in the women's keirin.
Canada has dominated the track cycling events, winning six gold, a silver and bronze.
The men's team pursuit squad of Calgary's Eric Johnstone, Hamilton's Sean MacKinnon, Remi Pelletier of Longueuil, Que., and Edward Veal of Queensville, Ont., beat Venezuela on Sunday to win bronze.
Two-time gold medallist Hugo Barrette earned bronze in the men's keirin final.