She topped the field in 11.67 seconds (-2.1m/s) ahead of University of Technology’s (UTech) Kemba Nelson, 11.87 and Holmwood Technical’s Sashieka Steele, 11.98.
Williams ran 11.53 (1.5m/s) in the heats to qualify on Friday.
Jamaica College’s Ryiem Robertson beat Calabar High’s Oblique Seville in the U20 boys’ final, 10.38 to 10.49. Seville won at Champs in 10.13s.
Kingston College’s (KC) pair of Adrian Kerr, 10.93, and Bouwahjgie Nkrumie, 10.94, finished first and second in the Boys’ Under-17 100m final.
Carleta Bernard of Mt. Alvernia won the girls’ U17 100m in 12.25, beating St Mary High’s Glacian Loutin, 12.34.
Peterfield High’s Shaquena Foote clocked 52.79 seconds to win the Girls’ U20 400m, beating Annakay Allen, 53.95 while York Castle’s Anthony Cox, 47.04, beat Calabar High’s Evaldo Whitehorne, 47.34 in the boys’ final.
Clarendon College’s Dejanea Oakley, 55.08 and JC’s Tariq Dacres, 48.97, won the Under-17 400m girls and boy’ finals.
In the field, Calabar High’s Kai Chang easily won the boys’ U20 discus throw with an effort of 61.68m. KC’s Ralford Mullings finished second with 57.15m.
Edwin Allen High’s Kimone Reid took the Girls’ U20 discus throw with an effort of 47.95, beating Excelsior High’s Adrienne Adams, 47.45m.
KC’s Jaheim Cox took the Boys’ U17 long jump with an effort of 7.06m. Edwin Allen High’s Paula-Ann Chambers, 5.74m topped the girls’ U17 long jump.