Margaret Mary O'Leary

Margaret departed this life peacefully January 20, 2026, after a lengthy struggle with debilitating health issues. Her faith was her strength through many trying setbacks. Margaret and her twin sister Ellen Claire were born in Jersey City, New Jersey to Margaret (Mulqueen) and Owen O’Leary. They were the oldest of five children including Thomas (deceased), Mary Anne Perkins (Arthur deceased) and Noreen Kozak (deceased).

Margaret graduated as a Registered Nurse from St. Mary’s Hospital School of Nursing in Hoboken New Jersey and attended Seton Hall University in Newark New Jersey. Her nursing career spanned 40 years including pediatric care, nursing management and occupational health. Beyond her professional life, her caring spirit was a gift to her family and friends. She was a lifelong dog lover, having trained and cherished a series of Bichon Frise and Keeshonds. She enjoyed reading, Irish music and keeping up with current events.

Margaret is survived by her sisters Ellen and Mary Anne, brother-in-law Ken Kozak, sister-in-law Eileen O’Leary, nephews Patrick O’Leary (Beth), Andrew Kozak (Kristin), William Kozak and nieces Kathleen Buscemi (Paul) and Megen Ory. Also, grandnieces and grandnephews Kayla and Ryan Kozak, Jamison and Brooks Buscemi and Andrew and Katie O’Leary as well as many wonderful cousins on both coasts.

The family wishes to acknowledge and thank the various health professionals who cared for Margaret through her difficult journey including James Leoni MD, caregivers provided by The Key Home Care, the Hospice Nurses from Providence Compassus (in particular Pierre and Sydney) and the drivers with Petaluma Paratransit (Deborah, Chris and Dana). Special thanks are due to Debi Benenson and Danielle Gray who were with Margaret the longest becoming close friends with their sensitive loving care.

Family and friends are invited to a vigil at Parent & Sorensen Mortuary in Petaluma on Monday February 2, 2026, at 6pm and to attend a mass Tuesday February 3, 2026, at 10:30am at St. James Catholic Church in Petaluma. Burial will be at Calvary Catholic Cemetery in Petaluma. A reception will follow at St. James Parish Hall.

In lieu of flowers donations may be made to the Franciscan Sisters of the Poor Foundation 505 Eighth Avenue Suite 900 New York NY 10018, St. James Catholic Church or a charity of your choice.