He bought the Colorado Rockies and in 1982 moved the team to East Rutherford, New Jersey renaming them the New Jersey Devils. He instituted the Dr. John J. McMullen Award in 1984, presented annually to "an individual or individuals who have supported amateur hockey throughout the state". The team won two Stanley Cups during his ownership, in 1995 and 2000. Just before winning the second Cup, McMullen sold the team to YankeeNets. After his death, the team dedicated the 2005–06 season to him, wearing a small "JM" patch on their jerseys.