Jon Tumilson got an early start on his preparation to join the SEALS. He had been a wrestler in high school and competed in marathons and triathlons.
Neighbors remembered the Rockford, Iowa, man as a warrior committed to the SEALs, no matter the pain he endured in training or the risks he ran on each mission.
"When he did something, he put his all into it," Jan Stowe, a neighbor of the Tumilsons for more than 30 years, told the Des Moines Register.
Tumilson, who was 35 when he died, "was going to be a Navy SEAL since I can't remember when," Stowe said. "He's like a hero to everyone here."
Another neighbor, Mark Biggs, said people were shocked by his death.
"You just never thought it would happen to Jon," Biggs told the Mason City Globe Gazette. "He's done so many dangerous things."
Friend Justin Schriever remembered Tumilson as "a die-hard at everything. He'd always go the extra mile on everything. He wouldn't let anything stop him from accomplishing something."