The band announced the death on Instagram on Sunday, writing that they were "devastated and shocked."
"On the morning of September 20, Chad Everett Gilbert passed away peacefully in his sleep. He left this world surrounded by friends and family, taking his final breaths with his wife and mother by his side, just as he wished," the band wrote.
Gilbert underwent brain surgery in March to remove three tumors. He had previously been treated for a rare form of cancer that had spread to his spine and lungs.
New Found Glory was formed in 1997 and has released 14 studio albums. In 2004 they played at Hovet in Stockholm.
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