Mary Margaret Vertin O'Neill

Mary Margaret Vertin O'Neill
09/02/2025
Mary Margaret Vertin O'Neill passed away peacefully in her sleep on September 2, 2025, in Oakland, California, at the age of 82.
Born in 1943 to Harold Edward and Mary Rentenbach Vertin, Mary grew up in Calumet, Michigan, and graduated from Sacred Heart Central High School in 1960. She earned her bachelor's degree in French from St. Mary's College, Notre Dame, Indiana in 1964. She later taught French in suburban Chicago.
While at St. Mary's College, Mary met her husband, David O'Neill, a Notre Dame student. They married in 1968 in Calumet and soon moved west, eventually settling in Berkeley, California, where they raised their family.
In the 1970s, 1980s, and into the 1990s, Mary devoted herself to family and to others, serving in leadership roles across her community including supporting the unhoused and numerous parent associations. Her community service was an inspiration to those who knew her. She also welcomed international students into the family's home, building friendships that endured for decades.
In 1993, Mary joined the development office at The College Preparatory School in Oakland, where she thrived for 16 years raising funds for an organization she deeply believed in. She retired in 2009 as director of development, often recalling, "Every day was fun," surrounded by bright students and dedicated teachers.
Mary traveled widely and formed lasting connections across countries and cultures. An educator at heart, she believed in learning from others and expanding perspectives through sharing connection and access to knowledge. One of her greatest gifts was building community, evident in her friendships, her work, her service, and her travels. She also cherished summers in Northern Michigan, where she was raised. She was a consummate cook and entertainer, and her chocolate chip cookies were legendary.
Mary was a longtime member of the Junior League of Oakland/East Bay, The Town and Country Club of San Francisco, and the Town and Gown Club of Berkeley, and served on the board of the Berkeley Public Library Foundation for many years.
Mary is survived by her husband and best friend of 56 years, David O'Neill; her children, Anne O'Neill (Michael Seel) and Thomas O'Neill; and her grandchildren, Catherine Seel and Joseph Seel. In addition to her parents, Mary was preceded in death by her brothers, Joseph Thomas and Harold Edward, Jr.
There will be a memorial service at Newman Hall-Holy Spirit Parish in Berkeley, California, on Friday, October 10, 2025.
In lieu of flowers, donations may be made in Mary's memory to The Berkeley Public Library Foundation [bplf.org] or The College Preparatory School in Oakland, California [www.college-prep.org