Kathleen "Katie" O'Brien passed away on January 11, 2026.

Katie was born on May 21, 1939, to Dr. John and Kathleen (Halferty) Bruen of Chicago, Illinois. She earned her BA and MA degrees from Mundelein College and Loyola University. As a BVM Religious, she spent 18 years in parish ministry and education.

Katie married Tom O'Brien in 1975. She continued her teaching career at St. Pius X School from 1979 to 1998 and was active in ministry and education with Pax Christi.

Katie is survived by her husband of 50 years, Tom O'Brien; her daughter and son-in-law, Meghan and Joe Karau; and her grandchildren, Tommy and Erin Karau, all of Rochester.

She was preceded in death by her parents; her sister, Doreen Vestal; and her brothers, George, John Dermot, and James Bruen.

A private family Mass will be held at a later date. Please feel free to leave online condolences at www.mackenfuneralhome.com . Memorials are suggested to Rochester Catholic Schools and the Rochester Public Library.