Of Sandy Spring, MD, formerly of Shadyside, died on Tuesday, December 16, 2025, at age 106. Preceded in death by her devoted husband of 59 years, William "Bill". Loving mother of Marian Sullivan of Brookeville, MD, and son-in-law, Joseph Hearst Sullivan. Also preceded in death by her parents Luigi and Angelina (Cannavina) Mastromonaco and seven brothers and sisters. Proud grandmother of David (Andrea), Linda (Cody Kelly), and Bill Sullivan, and loving aunt to many nieces and nephews. In recent years, Millie's greatest joy was her great-grandson, Renzo Joseph Sullivan (David and Andrea).

Family and friends are welcomed at the WALTER J. ZALEWSKI FUNERAL HOME, 216 44th Street, Lawrenceville, on Saturday, December 27, 2025 from 10-11 a.m. followed by a Funeral Mass at St. Jude Parish, Sacred Heart Church, 310 Shady Avenue, Pittsburgh, PA 15206 at 11:30 a.m.

In lieu of flowers, please consider donating to Saint Gianna Crisis Pregnancy Home (stgiannacph.org) in honor of Millie.