Sister Sheila Lyne earned her bachelor's degree in nursing in 1960 and a master's degree in psychiatric nursing in 1965, both from St. Xavier University, and her MBA from Chicago Booth in 1980. At Mercy Hospital and Medical Center from 1970 to 1991, she rose from director of the diagnostic and treatment center to president.
She was named deputy commissioner of public health for Chicago in 1990 and became commissioner in 1991. Lyne has been a board member for the American National Bank and Trust Company, American National Corporation, DePaul University, El Valor Corporation, Mercy Hospital and Medical Center in Chicago, Mercy Center in Aurora, the Illinois Hospital Association, and the State of Illinois Guardianship and Mental Health Advocacy Commission.
She has won numerous honors, among them the Excellence in Public Service Award from Crain's Chicago Business, North Business and Industrial Council, and Motorola, and the Shield of St. Xavier Award from St. Xavier University.