John B. “Jack” O’Callaghan, age 55, of Andover and formerly of Winchester, passed away on September 28, 2026. Jack was the beloved husband of Katie O’Callaghan and the loving father of Julia O’Callaghan. 

Born in Cambridge, he was the son of Mary Ann (Gibson) O’Callaghan and the late John F. O’Callaghan. He was raised in Winchester, graduated from Winchester High School in 1989, and earned his degree in Marketing from the University of Notre Dame. Jack spent many years as a dedicated medical device sales representative, proud to be part of a field that improved patients' lives. In his spare time, Jack enjoyed college football, spending time with friends, and sharing great stories. Above all, his favorite activity was watching his daughter, Julia, play soccer. Jack’s friendly personality and witty sense of humor will be deeply missed by all who knew him. 

Jack is survived by his wife, Katie; his daughter, Julia O’Callaghan; his mother, Mary Ann; his sister, Kelly Ann O’Callaghan, and he also leaves behind many aunts, uncles, cousins and friends. 

A Memorial Service will be held at the Parish of the Epiphany, 70 Church St., Winchester, on Thursday, October 8, 2026, at 10:30 AM. Relatives and friends are kindly invited to attend. A luncheon will follow at Meadow Brook Golf Club, 292 Grove Street, Reading, MA. 

In lieu of flowers, donations in Jack’s memory may be made to: Soccer Without Borders soccerwithoutborders.org , the Arbor Day Foundation (plant a tree in his honor), and the World Central Kitchen (food for those in crisis).