Faced with the challenge of selling a sport in an area that had never had major professional hockey before, Steve helped establish fan interest as the franchise debuted in their temporary home in the antiquated 11,000-seat Expo Hall on the Florida State Fairgrounds.

With the help of numerous large crowds in the immense dome, the Lightning finished the 1993–94 season second in the NHL in attendance, with a per game average of 19,398, second only to the Detroit Red Wings.

[5] In July 1994, Steve returned home when he was named president and Chief Administrative Officer of the Rochester Americans, who were owned at the time by Seymour and Northrup Knox of the Buffalo Sabres.

Under the leadership of Head Coach John Tortorella, the 1995-96 Amerks captured the American Hockey League crown in the Donner group's first year as team owners.

After a mediocre third-place division finish in the regular season, the Amerks swept the Adirondack Red Wings 3–0 in the opening playoff round and the Cornwall Aces 4–0 in the quarterfinals, and eliminated the Syracuse Crunch 4 games to 1 in the semifinals.

A thrilling 2–1 victory over the Portland Pirates at the Blue Cross Arena on June 13 gave the Amerks a 4–3 series win and the franchise's sixth and most recent Calder Cup championship.

[8] In the summer of 1995, Donner was at a baseball game with longtime friend and Rochester native Chris Economides, then owner of the Kansas City Attack of the indoor National Professional Soccer League.

Following a successful World Cup hosted by the United States in 1994, and with the forthcoming inauguration of MLS, soccer interest in the US was growing rapidly, and the two agreed that the timing was opportune.

[9][10] The team was christened as the Rochester Raging Rhinos, and former Lancer favorites Pat Ercoli and Frank Odoi were named as head coach and assistant.

After drawing respectable crowds at the 6,000-seat Fauver Stadium to begin the season, their move to Frontier Field made Rhinos games the place to be.

[13] In 2018, he led an ownership group called South Carolina Pro Hockey, LLC, that purchased the Greenville Swamp Rabbits of the ECHL.

[16] During the 2022-23 season Donner was implicated in controversy when it was discovered that a player, Nikita Andrusenko, who had been invited to training camp, was wanted in Utah for rape.