[2] Montour is of Mohawk descent and spent part of his childhood in Ohsweken, a village in the reserve of Six Nations of the Grand River.

[1] Montour began his professional career at age 21 with the Anaheim Ducks' affiliate, the Norfolk Admirals of the American Hockey League (AHL), towards the end of the 2014–15 season.

[16] He led Anaheim defencemen with 25 points through 62 games, however with the Ducks out of a playoff spot approaching the trade deadline, Montour was dealt to the Buffalo Sabres in exchange for Brendan Guhle and a 2019 first-round pick on February 24, 2019.

[18] After signing a three-year extension with Florida,[19] Montour experienced a breakout in the 2022–23 season, nearly doubling his personal best with 16 goals and 73 points, the latter of which tied for fifth in the league among defencemen.

[23] On April 29, 2019, Montour was selected to make his international debut after he was named to Canada senior team for the 2019 IIHF World Championship.

[24] On May 13, during a 6–5 victory over host nation Slovakia, Montour suffered a tournament-ending lower body injury, he finished scoreless through three games for Canada.