2009-10: Selected by the Calgary Hitmen in the sixth round (132nd overall) of the 2009 WHL Bantam Draft, Helgesen played for the Grande Prairie Storm Midget AAA team in Alberta. In 35 games he had 9 assists with 54 penalty minutes.
2010-11: Helgesen returned to Grande Prairie after attending the Hitmen's WHL training camp and played for the Storm in the Alberta Junior Hockey League. In 42 games with the Storm he scored 1 goal with 5 assists and had 39 penalty minutes. The Storm reached the playoffs after finishing fourth in the North Division. Helgesen skated in two of the five playoff games with no points or penalties.
2011-12: Helgesen skated in 58 games for Calgary in his first WHL season. He scored 3 goals with 11 assists and was plus-7 with 63 penalty minutes for the Hitmen. Calgary finished second to WHL champion Edmonton in the Central Division but fell to Brandon in a first round playoff series. In the five game series Helgesen was minus-three with 2 penalty minutes. He was invited to the NHL Draft Combine and ranked 64th amongst North American skaters in Central Scouting's final rankings prior to the 2012 NHL Draft.