His older brother, Chris, played quarterback for the Tampa Bay Buccaneers following an extraordinary career at Ramapo High School.

Matt attended Don Bosco Preparatory High School in Ramsey, New Jersey where he played quarterback on the football team for three years.

Though the team lost the state championship game his junior year, he was selected as a first-team All-State player by the Associated Press.

While at El Camino he led the team to its fourth consecutive league title and threw for over 2,000 yards in ten games.

[19] On August 29, the final preseason contest, Simms started and played the entire game against the Philadelphia Eagles.

[20] Simms threw his first career touchdown pass to tight end Jeff Cumberland in a Week 11 37–14 loss to the Buffalo Bills.

[21] During Week 13 against the Miami Dolphins, Simms came in relief of starter Geno Smith in the third quarter; he completed 9 of his 18 passes for 79 yards with an interception and a lost fumble in the Jets' 3–23 loss.

[28] However, after the team drafted Bryce Petty and signed undrafted rookie Jake Heaps, Simms requested his release and was granted it on May 28, 2015.

Late in that game, Simms, while trying to break a tackle, inadvertently threw the ball 20 yards backward, creating a loose-ball situation and setting the Lions up for the game-winning score.

[34] On September 3, 2016, he was waived by the Falcons as part of final roster cuts and was signed to their practice squad the next day.

[42] Simms started the 2019 AAF season opener against the Orlando Apollos, during which he completed 15 of 28 passes for 126 yards and two interceptions in the 40–6 loss.