Mayfield, a defenseman, was selected by the New York Islanders in the second round (No. 34) of the 2011 NHL Draft. The St. Louis native played two seasons with Youngstown of the United States Hockey League before deciding to follow in his father's footsteps and attend the University of Denver.
Mayfield played 81 games in two seasons (2011-13) with the Pioneers before turning pro. He joined Bridgeport of the American Hockey League after signing with the Islanders on April 5, 2013. He continued to take college courses online and earned his degree in business management from Colorado State College in 2016.