Executive Team

John Reilly is president and CEO of Six Flags Entertainment Company and also serves as a board director. He was appointed to these roles in December 2025.

Mr. Reilly has more than three decades of experience in the amusement and recreation industry, a proven track record of leadership in high-stakes environments, and significant operational management and strategic growth expertise. 

He most recently served as CEO of Palace Entertainment U.S. and group chief operating officer at Parques Reunidos, where he was instrumental in driving profitable growth and enhancing the guest experience across the company’s properties in the U.S., Australia and Europe.  Prior to Parques Reunidos, he served as COO and interim CEO at SeaWorld Parks and Entertainment, now United Parks & Resorts Inc., where he helped deliver meaningful EBITDA growth and total shareholder returns.

Mr. Reilly earned an MBA from the University of Miami and a B.A. from William & Mary. 

Tim Fisher is chief operating officer for Six Flags Entertainment Corporation. Tim retained the same role he held with Cedar Fair, L.P., where he joined in 2017. Tim has over 40 years of experience in the U.S. and international theme park industry, dating back to his first job at Carowinds in Charlotte, North Carolina.

As COO, Tim takes a hands-on and detail-oriented approach, ensuring the company’s long-range plan is executed with precision, and that the parks and resort properties perform to the company’s budgeted financial targets.

Prior to Cedar Fair, Tim served as CEO for three different regions of Village Roadshow Theme Parks in succession, including the North America region from April 2007 to January 2009; the Australia region through March 2017; and the Asia region through November 2017. Under Tim’s leadership as CEO, the theme park group achieved records for attendance, revenues and EBITDA performance. Prior to Village Roadshow, Tim was executive vice president of Paramount Parks and Viacom Recreation USA, where he was responsible for the management, operational and financial performance of all theme parks domestic and international until August 2006.

Tim previously served as a board director for Carlyle Group’s Apex Parks, and on the national board of A Kid Again, a non-profit organization that serves families with children that suffer from life threatening illnesses. Tim was awarded a BBA in Business/Marketing and an AA in Business Administration from American Intercontinental University.

Brian Witherow is chief financial officer for Six Flags Entertainment Corporation. He retained the same role previously held at Cedar Fair, L.P. where he was appointed as CFO in 2012. Brian served a pivotal role in guiding Cedar Fair through its 2024 merger of equals transaction with Six Flags Entertainment Corporation.

Brian is responsible for creating and executing a strategy to drive, account for and assess the effectiveness of the company’s entire financial enterprise. In this leadership role, which also includes oversight for information technology, Brian was integral in shaping Cedar Fair’s vision, long-term corporate mission and business strategy designed not only to build value for unitholders, but to also create lasting memories for Cedar Fair’s patrons.

Few people played a more consistent role in Cedar Fair’s accelerated period of growth than has Brian. He participated in or led teams through numerous acquisitions, which collectively added nine regional amusement parks and two waterparks to Cedar Fair’s asset portfolio across the U.S. and in Canada. Brian helped drive the game-changing acquisition of the Paramount Park properties from CBS in 2006, an ideal cultural fit that added significant, well-market positioned park assets from coast to coast in the U.S. and in Ontario, Canada.

He began his career with Arthur Andersen, having earned a bachelor’s degree in accounting from Miami University. Brian left public accounting in 1995 to join Cedar Fair as corporate director of investor relations. He was promoted to corporate treasurer in 2004 and named vice president and corporate controller the following year.

Brian Nurse is chief legal and compliance officer and corporate secretary for Six Flags Entertainment Corporation. He retained the same role previously held at Cedar Fair, L.P., since 2021. Brian has more than 25 years of comprehensive experience with some of the best-known entertainment and food and beverage companies in the world.

Prior to joining Cedar Fair, Brian was senior vice president, general counsel and secretary for World Wrestling Entertainment, an integrated global media company with revenue of approximately $1 billion. In that role, which he held for just over two years, he was responsible for all legal affairs and served as a member of the senior management team. Before that, Brian served six and a half years as vice president, associate general counsel and secretary at Nestle Waters North America, leading the day-to-day legal affairs for the $4.6 billion division of Nestle S.A., the largest food and beverage company in the world. From 2003-2012, he was senior legal counsel for PepsiCo, Inc., where he was lead counsel for North American beverage/soft drinks brands. Brian’s responsibilities included working with brand and sports marketing, licensing and branded entertainment. He joined Pepsi’s corporate law team as legal counsel in 2001.

Brian earned a bachelor’s degree from the University of Pennsylvania’s Wharton School and a juris doctor from Fordham University School of Law. He is a member of the American Bar Association and the New York State Bar Association.

Christian Dieckmann is the chief commercial officer of Six Flags Entertainment Company. He previously served as chief strategy officer for the company from 2023 until April of 2025. In his current role, Christian has assumed expanded responsibilities covering Marketing, Business Intelligence, Workforce Management and In-Park Revenue while continuing to oversee Strategic Alliances and Corporate Communications.

Christian has a track record of driving strategic growth opportunities including taking ideas from strategy to execution and championing revenue growth initiatives. He helped lead the Six Flags and Cedar Fair merger that closed in 2024 and has been supporting the integration activities of the combined company since the transaction. Coming out of the pandemic, Christian also led a major internal reorganization effort to develop new centralized capabilities like procurement and business intelligence at Cedar Fair. This enhanced platform for scalable growth has helped establish a strong foundation for the now combined company’s ongoing merger integration efforts. He first joined Cedar Fair in 2014 in a role focused on strategic growth, business development and innovation. 

Christian began his career at GE Capital, including roles in the company’s Financial Management Program and Internal Audit teams in both the U.S. and Europe. He later worked at Bain & Company where he advised Fortune 500 and private equity clients on strategy, M&A, merger integration and performance improvement. He also served as Chief Strategy Officer at Liminal Space, an early-stage technology company in the immersive entertainment industry. 

Christian earned his MBA from The Wharton School at the University of Pennsylvania, where he pursued a dual degree as part of the Lauder Institute’s international business program. 

Dave Hoffman is chief accounting officer for Six Flags Entertainment Corporation. He retained the same role previously held at Cedar Fair, L.P., since 2012. In his position, Dave comes in contact with nearly every financial data point collected, measured, and reported by the company. He provides oversight for finance and accounting, corporate tax, external reporting and financial policies, procedures, and controls. Dave also serves as counselor to the CFO.

As CAO, his primary focus is to advance the company’s technical competency through a period of rapid growth and expansion, in both scope and scale. Pivotal to that goal, Dave led a Cedar Fair initiative to modernize the way in which technical information is collected, managed, and reported. The project’s objective was to streamline the flow of information from multiple data gathering and reporting systems to a centralized data repository, furnishing management with contemporaneous and essential intelligence and insight about park operations and performance.

Prior to becoming CAO, Dave was Cedar Fair’s vice president of finance and corporate tax, since 2010. He joined the company in 2006 as vice president of corporate tax. Before working for Cedar Fair, he served as a business advisor with Ernst & Young. Dave earned a Bachelor of Science degree in accounting from the University of Toledo and a Master of Business Administration degree from the University of Michigan. He is a member of AICPA and OICPA.

Ty Tastepe is chief digital and technology officer for Six Flags Entertainment Corporation. He retained the same role previously held at Cedar Fair, L.P., since 2021.

Ty’s expertise in consumer-facing technologies propelled Cedar Fair’s guest satisfaction scores to new highs by implementing enhancements to the consumer’s online and park app experience. Ty also led initiatives to improve the Company’s enterprise-wide systems, the control environment behind those systems and data security in general.

Prior to joining Cedar Fair, Ty served for over two years as senior vice president, chief information and digital officer for Altar’d State, a fast-growing fashion retailer based in Tennessee with more than 120 stores in over 30 states. Prior to that, he spent nearly two decades delivering large-scale digital transformation programs for global brands such as Universal Parks and Resorts, Hilton Hotels, and Walt Disney Parks and Resorts. From 2001-2011, Ty held technology leadership roles at Disney Parks that included worldwide sales and travel operations, revenue management and marketing.

Ty earned an MBA from Villanova University and received both bachelor’s and master’s degrees in electrical engineering from Drexel University.

Seenu Sarma is chief procurement officer for Six Flags Entertainment Corporation. He retained the same role previously held at Cedar Fair, L.P., since 2021.

Seenu joined Cedar Fair to lead a transformational initiative to centralize procurement activities across the Company’s entire portfolio of entertainment properties to optimize the infrastructure’s efficiency and cost structure. His strategic expertise in designing and building centralized procurement programs and broad-based experience for world-class companies including NASA, helped Cedar Fair streamline the acquisition of equipment, products and services, and improve operational effectiveness. Prior to joining Cedar Fair, Seenu was chief procurement officer for Dean Foods, one of the nation’s largest food and beverage companies, where he led the centralization and transformation of the procurement function. Before that, he was a leader in Deloitte Consulting’s supply chain group for 18 years. Prior to his role at Deloitte, Seenu was an engineer and flight controller for NASA’s space shuttle program, supporting more than 30 flights in Mission Control.

Seenu holds an MBA in finance and corporate strategy from the University of Chicago, and master’s and bachelor’s degrees in electrical engineering, respectively, from the University of Houston and Rose-Hulman Institute of Technology in Terre Haute, Indiana.