A native of Melrose Park, Illinois, Schillace was attending Northern Illinois University and played softball in a Chicago league, being a member of the Illinois state and Chicago city championship teams. She impressed the AAGPBL scouts with her speedy baserunning and fielding skills. After receiving a tryout invitation, she became one of the first four players signed by the league for its inaugural season, joining Ann Harnett, Shirley Jameson and Edythe Perlick.
Schillace spent four years in the league, all with the Racine Belles. She had an outstanding rookie season, hitting a career-high .251 average, being selected to the All-Star Team, and as member of the 1943 Belles Championship Team. During her career, she posted a .202 average and stole 153 bases.
Following her baseball career, Schillace completed her studies and earned a master’s degree in education. After being married, she changed her name to Claire Schillace Donahoe. She and her husband had four children, three boys and a girl. For many years she worked as an educator in Maryland.