Martinez's wife, Olivia, on Wednesday told The Associated Press that he died Tuesday after suffering a heart attack while receiving dialysis. She said that her husband leaves behind three adult children and their spouses and also six grandchildren -- with a seventh soon on the way -- as well as an indelible impact on hundreds of young athletes from across the country.
"Tom had a very, very unique way of communicating with his athletes that resulted in a bond that was very special," she said. "First and foremost, he was a teacher, then a coach. His approach made the complex easy to understand. He truly was a master teacher in that respect."
Brady posted a statement on his Facebook page.
"I am deeply saddened by the passing of my coach, mentor and friend," he said. "Coach Martinez's invaluable assistance and support will never be forgotten and will always have a lasting impact on my life. The time we spent together remain some of my fondest memories. His legacy of commitment, toughness and determination will live on forever."
Olivia Martinez added that her husband reveled in helping young people while they were still defining who they were and in playing a small role in their maturation.
"He loved looking at them complete tasks that they hadn't been able to do before," she said. "They motivated him, and frankly, I'm convinced that kept him alive much longer than expected.
"I feel such a sense of loss, not only for our entire family, but for the kids who he coached and mentored and their families as well."
The Patriots offered their condolences to the family on Tuesday night via Twitter.
"Our sincere condolences go out to the Martinez family & all those he mentored throughout his incredible career," the team wrote.
Martinez, whose health had been declining due to complications from diabetes, was seeking a kidney transplant. He had been a mentor to many football players in the Bay Area.
"We were convinced the dialysis was slowly killing him," Olivia Martinez told the New York Daily News on Tuesday. "This is just oh, so sad. He had so much to teach people."
Brady's father, Tom Brady Sr., called Tom Martinez's passing "a big loss," and called his son and Martinez "soul brothers."
"Tom was just a terrific guy," Brady Sr. told ESPNBoston.com's Mike Reiss. "It's just a real sad day because he has coached and mentored and parented so many kids for so many years. He was a tough coach who was extraordinarily well respected. He just loved his kids, loved to get the best out of them. When kids got out of his programs, they all came back to visit him. He was a real wonderful, wonderful guy."
Brady Sr., repeating something he's said in the past, told Reiss, "Without Tom Martinez, there never would have been a Tom Brady with the New England Patriots."
In the days leading up to Super Bowl XLVI, Brady discussed the influence Martinez has had on his career.
"He's obviously a great friend of mine and a great friend of my family's, and has been for a long time. He taught me how to throw the football at a young age. I'm forever indebted to him," Brady said at the time.
"We've worked together for over 20 years trying to work on my mechanics and nail those down. He's had a great commitment to me. He's always calling and texting and saying, 'Get your shoulder down and get your arm up and close your left side and take a shorter stride.'
"Talk about a perfectionist, he's a perfectionist and he doesn't let anything slide with me. I owe so much to him. I love him. I love his family. He's got a great family, and I enjoy being with him and working with him."
Martinez was hired at College of San Mateo to coach football and teach physical education but added softball and women's basketball to his coaching load.
His teams won 32 championships. He had 400 career wins in football, a state record 565 wins in basketball and 800 wins in softball over 32 years, the Daily Journal reported.
"He really was the representation of Bulldog athletics," said College of San Mateo athletic director Gary Dilley. "It's great (Martinez) made such a great contribution to Tom Brady, but really the mark he made was in the hearts he trained and coached at CSM."
On Twitter, Patriots receiver Julian Edelman said Tuesday: "RIP coach Tom Martinez. He was such a great mentor to many in the bay area. His legacy will always live on."
A memorial service for Martinez is scheduled for 2 p.m. PT Friday at Menlo Park Presbyterian Church.
Information from ESPNBoston.com's Mike Reiss and The Associated Press contributed to this report.