While the Mathers era in Hershey started slowly with a fourth-place finish in 1956–57, he led the Bears back-to-back Calder Cup titles in his second and third seasons as a player-coach. With Bobby Perreault and Mayer in goal, the league's top two scorers in linemates Marshall and Dunc Fisher, and Mathers himself earning All Star honors on defense for the sixth time in seven years, the Bears won both the regular season and play-off championships in 1957–58. Although Hershey finished the 1958–59 season with just a .500 record (32-32-6), they defeated the Cleveland Barons in the first round before upsetting the regular-season champion Buffalo Bisons in the finals, four-games-to-two, to win their third Calder Cup title.