FRANK OTTO MATTFELD of NAPLES, FL passed away on October 6, 2026, at the age of 90 surrounded by his loving family. Born on October 27, 1935, he was the son of Heinrich Mattfeld and Rosalia Urban Mattfeld. Frank was one of six children, three older siblings, Helen, Ruth, and Hank and two younger Liz and Pat. After graduating from Sacred Heart Grammar School, Frank at the age of 12 joined the Franciscan Seminary in Callicoon, NY where he completed high school and Junior College. He followed by entering the Novitiate to study to become a priest in the Order of the Friars Minor (OFM). After completing the sixth year of seven, he ended his journey into the priesthood and enlisted into the Navy, where he served honorably for 4 years, specializing in Electronics and achieving the rank of third-class petty officer.
After graduating with his Master’s Degree in Education from Seton Hall, Frank began his new career in education. While teaching Latin to middle schoolers in the local New Jersey public school system, Frank also taught CCD classes for several years at his local church and parish. Three years later, Frank moved to Setauket, Long Island, New York. There he joined the Three Village School District as a Latin teacher, later a Department Chair of Languages, and soon after becoming the Assistant Principal of R.C. Murphy Junior High School. He retired after 30 plus years working in the public school system. Frank possessed a rare and gentle kindness that drew people to him instantly. He found his true calling in guiding and administering to middle school students. Frank understood the unique challenges of those transitional years and met students with a welcoming smile and an open heart.
Frank had many interests and hobbies over the years including stamp and coin collecting, crossword puzzles, card games, bird watching, playing the horses, family photography, cooking, John Wayne films, Neil Diamond and James Taylor music, writing and poetry, jogging, boating, fishing, softball and golfing. Additionally, he was passionate about watching his favorite sports teams: the Yankees, Rangers, Seton Hall, Notre Dame and the alma maters of his kids and grandchildren. Fantasy football and the Olympics were also highlights for him.
Frank’s love of open skies and warm waters brought him to the Sunshine State where he enjoyed his final years. After snow-birding for many years, Frank finally retired to Naples, FL in 1990, waiting for Kathi to join him after her retirement from teaching. He was an original owner of the new condo community at Countryside GCC, forming new friendships as he indulged in his love of golf (actually hitting a Hole-in-One!). Retirement gave Frank the freedom to travel more with family and friends, meeting new grandchildren and great-grandchildren, creating new memories as he lived the Florida life.
He is survived by his loving wife Kathryn Matos, of 24 years; his children with his first wife, Audrey: Stephen Francis Mattfeld (Ann), Kenneth Francis Mattfeld (Colleen), Raymond Francis Mattfeld (Dawn), and Michael Francis Mattfeld (Sandy); eight grandchildren: Amanda Dwyer (Brian), Ryan Mattfeld (Valerie), Brittany Craig (Jack), Jessica Mattfeld (Chris), Casey Mattfeld, Megan Mattfeld, Elizabeth Mattfeld, and Cate Mattfeld; and six great-grandchildren: Vivienne, Oliver, Charlie, Bobby, Eloise, and including a Baby Girl To-Be (04/27). In lieu of flowers, donations may be made to Hope House Ministries or Infant Jesus RC Church Social Ministries for the Food Pantry.
Visitation will be held at O. B. Davis Funeral Homes, 4839 Nesconset Highway, Port Jefferson Station, NY 11776, on October 24, 2026, from 2:00 pm to 4:00 pm and from 7:00 pm to 9:00 pm, and on October 25, 2026, from 2:00 pm to 4:00 pm and from 7:00 pm to 9:00 pm.
A Funeral Mass will take place at the Infant Jesus Chapel at St. Charles, 200 Belle Terre Rd, Port Jefferson, NY 11777, on October 26, 2026, at 10:30 am.
Committal Service with Military Honors to follow at Calverton National Cemetery, 210 Princeton Blvd, Calverton, NY 11933.
