In 1991, Sumich kicked 111 goals to finish second in the Coleman Medal to Tony Lockett, establishing records as the only West Coast Eagles player to kick more than 100 goals in a season and becoming the first left-footer to kick more than 100 goals. His total of 89 behinds for the season is also a VFL/AFL record. Against Footscray in round 13 he kicked 13.3, surpassing his previous record for most goals in a game (later topped by Scott Cummings in 2000 with 14.1). He also kicked five goals in West Coast's Grand Final loss to . Sumich was a member of West Coast's 1992 and 1994 premiership victories over , kicking six goals in the 1992 Grand Final and two goals in the 1994 Grand Final.