 Hangsleben made a total of 334 WHA game appearances for the Whalers in 1975–1979.The Canadiens, who still retained his NHL rights, left him exposed for the 1979 NHL Expansion Draft, and he was claimed by the Hartford Whalers when they were admitted into the NHL in 1979.Hangsleben was traded to the Washington Capitals during the middle of the 1979–80 NHL season in exchange for Tom Rowe, and played for the Capitals until he was released early into the 1981–82 NHL season.