Stewart keyed a tough defense with four blocks while Kaleena Mosqueda-Lewis added 16 points and Bria Hartley provided 15 points and four steals off the bench for the Huskies (34-4), who had dropped three straight to Notre Dame this season.
The Huskies, who last fell to the Fighting Irish in the Big East Tournament, now go on to seek their eighth NCAA tournament title Tuesday against Louisville.
The Cardinals bested California in Sunday's first national semifinal.
Kayla McBride led Notre Dame (35-2) with 16 points and six rebounds. Jewell Loyd also reached double figures with 11 points, while Skylar Diggins added 10 points, eight assists, four steals and three blocks for the Irish.