John Mark Stanley

John Mark Stanley passed away on October 11, 2026 at the age of 86. He was born August 22, 1940 in Chicago, Illinois to Steve and Nancy Stanley. He was a beloved son, husband, father, grandpa, great-grandpa, brother, uncle, cousin, and friend.

John married the love of his life, Marilyn, on September 5, 1964. They were blessed with 62 wonderful years of marriage.

He was preceded in death by his parents, his baby sister Eileen Stanley, and his parents-in-law Bob and Agnes Chapman as well as brother-in-law David Chapman and beloved extended family.

He is survived by many who will cherish his memory. His beloved wife Marilyn and their three daughters Theresa Zinsmeister (David), Deborah Tschirhart (David), and Stephanie Zinsmeister (Patrick). He is survived by 13 grandchildren: Nathan Zinsmeister (Tammy), Andrew Zinsmeister (Melissa), Ellen Jambers (Troy), Rebecca Zinsmeister, Thomas Zinsmeister (fiancé Naila), Sabrina Tschirhart, Samantha Merz (David), Matthew Tschirhart, James, Ethan, Eileen, Amy, and Emily Zinsmeister and nine great-grandchildren: Gideon, Zane, Jesse, and Audrey Zinsmeister, Toby and Jeremiah Jambers, Dinah, Davey, and Piper Merz. He is survived by beloved sisters-in-law and brothers-in-law, Eileen Casterline (Jerry), Christine Schwanz, Rita LaFace (Alan), Daniel Chapman (LeAnn), and Margaret Ahr (Gene), as well as their children and grandchildren. He is also survived by numerous cousins on his Dad’s side.

John earned his Bachelor of Science degree in Electrical Engineering from Loyola University of Los Angeles. After joining the Air Force, he earned his Masters of Science degree in Electrical Engineering from the Air Force Institute of Technology. Dad served for 20 years in the Air Force, and he was awarded the Meritorious Service Medal before retiring as a Major. After retiring, he earned his teaching certificate and taught math at Holmes High School for 20 years. He taught Advanced Calculus classes and helped grade the Calculus Advanced Placement exams every summer for many years. Then he started teaching Advanced Calculus classes at UTSA which he did for over 10 years. He was very dedicated to the success of his students and continued tutoring Calculus online until he was 81 years old.

John loved to serve and help others through volunteering as the president of St. Vincent de Paul Society at St. Luke’s Catholic Church for six years as well as volunteering with the St. Luke’s Men’s Club. John had recently been recognized and honored for his contribution as SVDP president at a Christmas function at St. Luke’s in December of 2023. He also served as an organist for 13 years, as well as lector and communion minister for many years.

John had many interests, but he especially enjoyed playing dominos, bowling with Marilyn and their friends, and playing the piano. He began learning piano at age nine and continued throughout his life. He shared his gift by teaching his three daughters. He and his daughter Deborah shared their love of piano together by playing numerous duets just for enjoyment and at family functions, and also at St. Louis Catholic Church in Castroville for Masses with Deborah during the Christmas season and patriotic holidays. They also won a piano state competition together in 1990.

John will be remembered by his great love and ongoing support for his family, and his wonderful example of his Catholic faith and strong relationship with Jesus. John and Marilyn put their faith and family first, and they enthusiastically supported their children’s and grandchildren’s extracurricular activities. John’s family, friends, and co-workers loved and respected him so much for his kind and gentle ways, and will always remember him for his quick wit and puns as well. The family wishes to extend our deepest gratitude to all of John’s caregivers for their thoughtful support, loving concern, and diligent care of our dad. He will be greatly missed.

Visitation will be held at Sunset Northwest Funeral Home, 6321 Bandera Road, San Antonio, Texas 78238, on November 4, 2026, from 5:00 pm to 8:00 pm. A Rosary will be held at Sunset Northwest Funeral Home, 6321 Bandera Road, San Antonio, Texas 78238, on November 4, 2026, at 6:00 pm.

A Funeral Service will be held at St. Luke Catholic Church, 4603 Manitou Drive, San Antonio, Texas 78228, on November 5, 2026, from 10:00 am to 11:00 am. A Committal Service will be held at Fort Sam Houston National Cemetery, Shelter #3, 1520 Harry Wurzbach Road, San Antonio, Texas 78209, on November 5, 2026, at 11:30 am.