Following a brief 12 games in the International Hockey League (IHL) with the Muskegon Mohawks, he retired and became the head coach.
Popiel and Garry Peters were co-winners of the inaugural Ken McKenzie Trophy as Central Professional Hockey League rookies of the year in 1963-64.
His younger brother Jan Popiel is also a former professional hockey player.
[1] Popiel's family moved to Canada in 1951 when he was a child, and subsequently moved to the United States and he acquired American citizenship before making his NHL debut.
This Danish biographical article relating to ice hockey is a stub.