CHARLOTTE, N.C. – Six Flags Entertainment Corporation, the parent company of Dorney Park, has picked a new leader.

John Reilly has been named the struggling amusement park operator’s President and Chief Executive Officer (CEO), effective Dec. 8. Reilly will also join the company’s Board of Directors.

Reilly recently served as CEO of Palace Entertainment U.S. and Group Chief Operating Officer at Parques Reunidos, an amusement park operator based in Madrid, Spain. He also previously held similar roles at SeaWorld Parks and Entertainment.

Reilly succeeds Richard Zimmerman, who, as previously announced in August, is stepping down as President and CEO. Zimmerman will also step down from the board.

Six Flags, the largest regional amusement park operator in North America, is no doubt hoping for a few less stomach-churning thrills and ups-and-downs when it comes to the business side of things.

The company has struggled financially since its $8 billion merger last year with the Ohio-based Cedar Fair, which brought sites including Dorney Park and Wildwater Kingdom in Lehigh County under its umbrella.

Shares of Six Flags stock (NYSE: FUN) have dropped about 67% since the beginning of the year. The company previously said it would be eyeing underperforming parks for possible sale but did not specify which ones.

Six Flags is also the subject of a federal class action lawsuit that alleges shareholders were burned because the company oversold its financial health and the status of its parks prior to the merger.

In a news release announcing Reilly’s appointment, Marilyn Spiegel, Chair-elect of the Six Flags Board, said he was joining the company at a critical moment: “With a fresh set of eyes, combined with significant experience optimizing theme park operations and performance, we believe John will harness the best of both legacy companies and will reinvigorate profitable growth at our underperforming parks.”

The announcement was also applauded by JANA Partners, an investment firm that recently purchased a 9% stake in Six Flags. The head of JANA Partners, Barry Rosenstein, is a Lehigh University graduate. The group also includes NFL player Travis Kelce.

Shares of Six Flags were up about 7% at the end of trading on Monday; they opened about 1% higher on Tuesday at $14.59.