Brayden McNabb was born on January 21, 1991in Davidson, Saskatchewan. The hulking defenceman made his debut for the Kootenay Ice of the Western Hockey League during the final stages of the 2006-07 season. He would spend the next three seasons with the club, putting up improved offensive numbers each year. He was chosen 66th overall by the Buffalo Sabres in the 2009 NHL Entry Draft.
McNabb would split time during his first professional season (2011-12) between the Buffalo Sabres and their AHL affiliate, the Rochester Americans. At the NHL level, he would appear in 25 games, recording a goal and adding seven assists. In the AHL, he registered five goals and 25 assists in 45 games.
On March 5, 2014, the Sabres traded McNabb, along with Jonathan Parker and two draft picks, to the Los Angeles Kings for Hudson Fasching and Nicolas Deslauriers.