The geography teacher and cross-country coach helped students enter a locked classroom to avoid the gunman before being fatally shot at Marjory Stoneman Douglas High School in Parkland.
Beigel grew up on Long Island and worked as a counselor at Camp Starlight in rural Pennsylvania, which posted a tribute to him on its Facebook page.
Student Kelsey Friend spoke on Good Morning America Thursday, crediting Beigel with saving her life.
"He unlocked the door and let us in," she said. "I thought he was behind me, but he wasn't. When he opened the door, he had to relock it so we could stay safe, but he didn't get a chance to."
Friend said Beigel will forever be her hero.
"If the shooter would have come into the room, I probably wouldn't be speaking to you now," she said. "I don't know how we're alive."
RELATED: These are the Florida school shooting victims.
Beigel's funeral is scheduled for Sunday at a synagogue in Boca Raton, Florida.
* More Long Island news
* Send us a news tip
* Download the abc7NY app for breaking news alerts