He played college football for the UConn Huskies and Eastern Kentucky Colonels and signed with the Green Bay Packers as an undrafted free agent in 2018.

[1] A 3-star recruit, Boyle was the top-ranked quarterback in Connecticut his senior year, and accepted a scholarship offer from home state Connecticut over offers from Boston College, Delaware, Harvard, Houston, Maine, Massachusetts, Syracuse, and Western Michigan, as well as preferred walk-ons from Notre Dame, Oregon, Pittsburgh, and Rutgers.

[7][8] After an impressive preseason, Boyle made the 53-man roster in September 2018, as the team's third string quarterback behind Aaron Rodgers and DeShone Kizer.

Boyle took over for Rodgers during the final minutes of the game after victory was assured, kneeling the ball three times for −3 yards to run out the clock.

[10] He saw more extended playing time five weeks later on November 24 during a lopsided loss to the San Francisco 49ers, completing his first NFL pass to backup tight end Robert Tonyan, and finished the game 3-of-4 for 15 yards.

[16] He made his second career start in a Week 16 game against the Atlanta Falcons with Goff sidelined due to COVID-19, completing 24 of 34 pass attempts for 187 yards and a touchdown, but also threw a loss-sealing interception with less than a minute to play on goal-to-go, losing 20–16.

[26] On November 19, Boyle replaced Zach Wilson late in the third quarter and completed 7 of 14 passes for 33 yards and an interception in a 32–6 loss to the Buffalo Bills.

[33] Boyle appeared in the Dolphins' Week 3 game against the Seahawks after Skylar Thompson left in the second half with a rib injury.