A spokesman for the Giants said the team had been briefed by close friends of Fassel’s family.
Fassel, who had lived outside of Las Vegas, was rushed to hospital on Monday with chest pain and died of a heart attack under sedation, according to the Giants, citing numerous media reports.
Fassel led the Giants to the playoffs three times during his tenure on the team, including a Super Bowl appearance in 2001 where New York lost to the Baltimore Ravens in Super Bowl XXXV.
He trained at the college and professional levels for 30 years, with stints as head coach at the University of Utah and assistant coaching roles with the Denver Broncos, Oakland Raiders, Arizona Cardinals and Baltimore Ravens.
Fassel trained Hall of Famer John Elway as an offensive coordinator at Stanford and the Denver Broncos.
But it was Fassel’s seven seasons with the Giants that he valued the most.
“People ask me, ‘Wasn’t the media terrible for you?’ No, I am friends with many of them. I respect the media. You have a job to do. Tell you what, I’ve been to (five) different franchises (including Baltimore where he was an assistant giants) but at the Giants I learned to coach in the NFL, mostly from George Young (the late General Manager and Pro Football Hall of Famer). You’re doing it right. You line up the marbles to win. “
Fassel was the head coach of the New York team at the time of the September 11, 2001 terrorist attacks. He was at the forefront of the Giants’ efforts to help the city recover.
“I went there three or four days later and it was amazing. You stand there and this space is just wide open. I asked her, ‘What should I do?’ They said, “You can cheer them up. People recognize you, you can just support them.” So I did that. And it worked. That’s how I came into contact with some fire fighters for the first time. Even those from abroad, mostly some from California, recognized me, and I stopped and spoke to them. These guys looked like they didn’t sleep in days, they were dirty. I just said, ‘Thank you guys for what you’re doing here.’ You’re trying to do a little something for her. “