[3] After Maxwell was benched, Cook helped lead the team to a win in the 2012 Buffalo Wild Wings Bowl, completing four of 11 passes for 47 yards and a touchdown.
[9] As a senior in 2015 Cook led the Spartans to a 16–13 win over the Iowa Hawkeyes in the Big Ten Championship Game and was named MVP for the second time in three years.
The victory in that Big Ten Championship Game earned them a spot in the College Football Playoff (2015 Cotton Bowl), where they lost to the Alabama Crimson Tide, 38–0.
He won the 2015 Johnny Unitas Golden Arm Award as the nation's outstanding senior or fourth year quarterback.
[16] Cook began his rookie season for the Raiders as the third-string quarterback on the depth chart behind starter Derek Carr and second-stringer Matt McGloin.
On December 24, 2016, Cook was raised to backup quarterback after Carr suffered a season-ending right fibula injury.
On January 1, 2017, Cook made his NFL debut, entering the game late in the first half after starter McGloin suffered a shoulder injury.
[18] On January 4, Cook was named the starter for the American Football Conference (AFC) Wildcard Game against the Houston Texans.
[19] McGloin was limited in practice due to his injury but was still active as Cook's backup for the playoff game.
[20][21][22] Cook became the first quarterback in the Super Bowl era to make his first career start in a playoff game.
[23][24] On January 7, 2017, in the AFC Wildcard Game against the Texans, Cook completed 18 of 45 passes for 161 yards, one touchdown, and three interceptions as the Raiders lost 27–14.