McWilliams played Janet Mason for six years on GUIDING LIGHT from 1969 to 1975 and originated the role of Tracy DeWitt on ANOTHER WORLD in 1976 (later played by DIARY OF A SINGLE MOM's Janice Lynde). She also played LuAnn Pruit on BEVERLY HILLS, 90210 and Marcy Hill on the sitcom BENSON.
On Broadway, she was a cast member of the 1975 revival of "Cat on a Hot Tin Roof," as well as "The Rothschilds," and "Boccaccio." Off-Broadway, she worked for the Public Theater and the American Shakespeare Festival.
She is survived by her son Sean Douglas and her sisters, Patti McWilliams, Norma Liedtke, and Kelly-Jo Dvareckas.