Cook left the Barons to join the Minneapolis Millers of the United States Hockey League (USHL) in 1947. He coached the team for three seasons, leading the team to the Paul W. Loudon Trophy as league champions in 1949–50. He moved on to coach the Denver Falcons, also of the USHL, in 1950–51 then the Saskatoon Quakers of the Pacific Coast Hockey League (PHCL) the following season. Cook left the Quakers midway through the season when asked by Frank Boucher, general manager of the New York Rangers, to return to the NHL club as its head coach. He coached the final 47 games of the Rangers' 1951–52 season, winning 17, losing 22 and tying 8. He remained behind the Rangers bench in 1952–53, but the Rangers missed the playoffs after winning only 17 of 70 games. Cook was replaced as coach following the season as Boucher named himself head coach. Cook then retired from hockey.