The Buffalo Sabres selected Hagel, a forward from Morinville, Alberta, in the sixth round (No. 159) of the 2016 NHL Draft after his first season with Red Deer of the Western Hockey League. However, they lost their draft rights after not signing him before the 2018 NHL Draft. He was not selected and agreed to terms with the Chicago Blackhawks as a free agent Oct. 30, 2018.
Hagel completed his fourth and final season with Red Deer in 2018-19, scoring 41 goals and 102 points in 66 games. He set the Red Deer career record for assists with 176 before turning pro with Rockford of the American Hockey League after the WHL playoffs.