PRAIRIE DU SAC, Wis. -

The CEO and president of Culver's died of natural causes Saturday, a company spokesman said.

Director of communications Paul Pitas said Phil Keiser, 60, worked for Culver's for 20 years. Keiser was the leader of more than 20,000 team members at 580 Culver’s restaurants in 24 states. He said Culver’s community is "devastated."

Co-founder Craig Culver will assume the role of interim CEO until a successor is named, according to a news release.

"Culver’s would not be what it is today without Phil’s influence," Craig Culver said. "Yet as great a loss as this is for us professionally, it doesn’t begin to touch how much Phil will be missed on a personal level."

Keiser is survived by his wife Betsy, his son, Nate (Bethany), and their children, Caprina, Linea and Landon; son, Nick (Maria), and their child Harper; and daughter, Kelsey.

Keiser had more than 35 years of food industry and strategic restaurant management experience. He joined Culver’s in 1996 and held several positions, including director of operations and vice president of operations, before he was named president and chief operating officer in 2003. He was named CEO in 2015. Pitas said that before joining Culver’s, Keiser held various management positions with Burger Chef and Hardee's.

Pitas said Keiser would have turned 61 years old Monday.

Culver's is headquartered in Prairie du Sac.