Coyle played college football at the University of Montana in Missoula. As a true freshman in 2009, Coyle collected 30 tackles and 2 interceptions for the Montana Grizzlies while playing linebacker. Coyle redshirted the 2010 season following off-season surgery. In 2011, after playing in all 14 games for the Grizzlies, Coyle finished the season as the team's 16th leading tackler despite not starting a single game. In 2012, Coyle enjoyed a breakout season when he started 11 games and tallied 107 tackles. His average of 9.73 tackles a game ranked him 28th in the nation, and he was an honorable mention All-Big Sky Conference selection. In 2013, Coyle had his finest college season with the Grizzlies while starting at inside linebacker as a redshirt senior. Coyle led the Grizzlies with 125 total tackles, which put him among the nation's leaders. He also forced 4 fumbles and intercepted 2 passes, giving him 5 total interceptions for his college football career. He was named to the 2013 Big Sky All-Conference Team as a second-team selection. While playing at the University of Montana, Coyle was teammates with future NFL linebacker Jordan Tripp and cornerback Trumaine Johnson.
Professional career
Seattle Seahawks
Although Coyle went undrafted in the 2014 NFL Draft, he was signed to a professional contract by the Seattle Seahawks just minutes after the draft's completion. Seahawks coaches praised Coyle for his productive play during the NFL preseason while he filled in for injured middle linebacker Bobby Wagner. Coyle started his first NFL regular season game at middle linebacker for the Seattle Seahawks on Sunday November 2, 2014 while playing against the Oakland Raiders. Coyle had a successful career with the Seahawks, mostly as a core special teamer, while also starting 5 games. Coyle tallied 33 tackles and 1.0 sack in three years. One of Coyle's best games was when he started at Strongside linebacker against the Buffalo Bills. On Monday Night Football, Coyle had his first career sack, along with 8 tackles on the night.
On March 10, 2017, Coyle signed a one-year contract with the San Francisco 49ers. On March 14, 2018, Coyle signed a three-year contract extension with the 49ers. He was placed on injured reserve on September 12, 2018 after suffering a concussion in Week 1. On March 14, 2019, Coyle was released by the 49ers, and subsequently announced his retirement from the NFL, stating that a broken bone in his back prevented him from returning.
