She was born Rose Marie Willett in Waverly, Kentucky, the daughter of Joseph Edward and Jane Isabel Perdue Willett.
An educator for 49 years, she taught at St. Denis School, Fancy Farm (1940-41), Sts. Joseph and Paul School, Owensboro (1951-65, principal 1959-65), St. Thomas More School, Paducah (principal, 1974-75), Immaculate Conception School, Earlington (1976-77), and St. Martin School, Rome (principal and teacher, 1977-78). She served as supervisor of the Owensboro Catholic Schools (1966-68). In 1976, she ministered to the Vietnamese at St. Peter of Alcantara Parish, Stanley.
In the Archdiocese of Louisville, she taught at Holy Cross School, Holy Cross (1945-51), and St. Edward School, Jeffersontown (1980-81), and served as coordinator of religious education for St. Ignatius Parish, Louisville (1981-82).
She also taught at St. Thomas School, Farmington, New Mexico (1941-45).
She ministered in religious education at St. Mary Parish and School, Mount Carmel, Illinois (1982-90), and was pastoral minister for St. Mary Parish (1992-94).
At Brescia College, Owensboro, Sister Rosita was a member of the faculty of the Department of Education (1965-66), registrar (1968-74), and administrative assistant in the Ministry Formation office (1994-96). She served in admissions at Mount Saint Joseph Academy (1978-80) and in hospitality ministry for Mount Saint Joseph Conference and Retreat Center (1990-91). She retired in 1996.
Survivors include three sisters, Sister Dorothy Marie Willett, Maple Mount, Kathleen Dunkel, Englewood, Ohio, and Doris Trapp, Mount Carmel, Ill.; one brother, Joseph Vernon Willett, Evansville, Ind.; nieces and nephews, and the members of her religious community.
Gifts in memory of Sister Mary Rosita Willett may take the form of donations to the Ursuline Sisters of Mount Saint Joseph, 8001 Cummings Road, Maple Mount, KY 42356.