All three players were signed by the
Boston Bruins, It was with the Reds that Bauer as
right wing, Schmidt at
centre and Dumart, who moved up to left wing, were first placed together as a
line. Owing to their shared German heritage, the trio were initially called the "
Sauerkrauts" by Providence coach
Albert Leduc, though the name was shortened and they were known as the "
Kraut Line" for the majority of their careers. The Kraut Line earned full-time spots in Boston beginning in
1937–38; Bauer recorded a team-leading 20 goals in his
rookie season as the trio led the Bruins to the team's first of four consecutive
Prince of Wales Trophy wins as the NHL's best team in the regular season. Following a 31-point regular season in
1938–39, Bauer added five points in 12 playoff games and was named to the NHL's
second All-Star team. In
1939–40, Schmidt led the NHL in points with 52 while Dumart and Bauer finished second and third respectively with 43 each. It was the first time in league history that three linemates finished in the top three spots in NHL scoring. Bauer was again named a second team All-Star, and with only two
penalties in minutes (PIM), won the
Lady Byng Trophy for the first time. Following the outbreak of the Second World War, all three members of the Kraut Line enlisted with the Canadian military by signing up for home defence. At the same time, anti-German sentiment led to efforts to change the trio's nickname. They were briefly called the "Buddy Line" and the "Kitchener Kids", though they were again referred to as the Kraut Line following the war. In their final game with the Bruins, the Kraut Line recorded eight points in a dominating victory over the
Montreal Canadiens. Following the contest, players from both teams fêted the trio, hoisting them up on their shoulders and parading them around the ice. Bauer was overwhelmed by the moment: "The ovation, at the height of my youth, sort of grabbed me." Schmidt, Dumart and Bauer were the first NHL players to join the
Royal Canadian Air Force, and while training in Ottawa, they joined the
Ottawa RCAF Flyers of the
Quebec Senior Hockey League (QSHL). Bauer was sent to
Halifax to continue his training and played with the Dartmouth RCAF team in 1942–43. He played with a team in Toronto until the war's conclusion. He chose to return for one additional season and was named the Bruins
captain for
1946–47. He was named to a fourth All-Star team and won the Lady Byng Trophy for the third time. Following the season, he announced his retirement. ==Coaching career==