John Callahan Jr., the founder and patriarch of construction firm John T. Callahan & Sons, died March 29 from complications of Alzheimer’s disease, his family announced this week. He was 90.

Callahan, who was better known as Jack, was born and raised in Randolph, Massachusetts. He and his wife, Marie, founded Callahan & Sons in 1954. The business went on to work with East Coast clients such as Sears, Dunkin’ Donuts, Burger King and Howard Johnson, and all five of the couple’s sons joined the family business.

Callahan & Sons eventually branched out into three entities, Callahan Construction Managers, Global Property Development Corp. and JTC III Development Corp.

Callahan, who played in the New York Baseball Giants' minor-league system, is remembered by his family for being good with his hands, quick with a joke and insistent on hard work.

“If we weren’t going to work the weekends, he’d fire us on Friday and hire us back on Monday," Stephen Callahan, the founder of Global Property Developers, said in a release.

“Much like following the kids in sports, he was especially proud of the businesses’ success and their dedication to a job well done and a happy client,” son Tim Callahan, a vice president at Callahan Construction Managers, said in the release.

Jack Callahan is survived by his five sons, 16 grandchildren and 15 great-grandchildren. His youngest son, Pat, is now president of Callahan Construction Managers.

"Our father taught us the keys to a successful business are strong relationships, excellence in service and community commitment,” Pat Callahan said in the relase. “My brothers and I look forward to continuing his legacy. Dad taught us that family extends beyond blood, and we have taken his approach into how we work with and treat our loyal staff across all of the Callahan Companies.”

The coronavirus pandemic has precluded a public celebration of life, but the Callahan family requests that, in lieu of flowers, mourners honor Callahan’s commitment to the support of first responders by donating in his memory to the Massachusetts COVID-19 Relief Fund.