DOVER — Greg Bostrom, who has been the director of the Firefly Music Festival in Dover since its inception four years ago, has left that post to take a job with the Minnesota Vikings.

According to Christiane Pheil, talent and experience director for the festival produced by Chicago-based Red Frog Events, Mr. Bostrom was named entertainment director for the football team last month.

His duties will include planning each home game’s halftime show as well as the Super Bowl halftime show when it comes to U.S. Bank Stadium in 2018.

Greg Bostrom, who has been the director of the Firefly Music Festival since its inception, has taken a new job with the Minnesota Vikings. (Delaware State News file photo)

Under Mr. Bostrom’s watch, Firefly, which is held at the Woodlands of Dover International Speedway, has gone from hosting an initial crowd of 30,000 people in 2012 to 90,000 last year, making it one of the largest music festivals in the country. Firefly has also grown in the number of stages and artists as well.

Ms. Pheil said Wednesday Red Frog is expecting an attendance figure of 90,000 again this year and Mr. Bostrom had a large hand in the planning of the 2016 event.

In 2014, Firefly grew from three days to four.

Past headliners have included Paul McCartney, Red Hot Chili Peppers, Foo Fighters, Outkast and Tom Petty.

“Our staff thoroughly enjoyed working with Greg from the first day we met him five years ago,” said Michael Tatoian, president and CEO of Dover International Speedway, in a statement.

“He was a terrific representative of Red Frog and of Firefly Music Festival and did a great job cultivating the event from the beginning to where it is today. His impact will be felt on the festival for a long, long time.”

Firefly Music Festival spokeswoman Lauren King said Wednesday that many of Mr. Bostrom's responsibilities have been absorbed by Stephanie Mezzano, Red Frog Events and Firefly's chief operating officer, adding that she's been overseeing the festival from behind the scenes since 2012 and has been at Red Frog Events since 2009.

This year’s festival will run from June 16 to 19 and include headliners Mumford and Sons, Kings of Leon, Florence + The Machine and Deadmau5.

Tickets, priced for four-day and one-day sales, are available at fireflyfestival.com.

EDITOR'S NOTE: Staff writer Ashton Brown contributed to this story.