Following his second season with the Millers, Dahlstrom made his first attempt at becoming a National Hockey League (NHL) player when he was invited to Boston Bruins training camp.

[2][3] Following his third year with Minneapolis he joined the St. Paul Saints and improved his point total to 36, playing 44 games.

[3] The following season the Saints changed leagues, joining the American Hockey Association (AHA).

[3] During this time Frederic McLaughlin was scouting the AHA for American talent for the NHL's Chicago Black Hawks.

[7] In game 4 Dahlstrom scored the first goal in a 4–1 win to capture the Stanley Cup, becoming the "most improbable" championship team in NHL history.

[15] The season proved to be Dahlstrom's most successful as he set career highs in games played, goals, assists, and points.

[11] Following the end of the season he was traded to the Seattle Ironmen in the Pacific Coast Hockey League (PCHL) for cash.

[4] In 1973 Dahlstrom was elected to the United States Hockey Hall of Fame as part of the inaugural class.