Vernon was one of the guilty players in the 2011 University of Miami athletics scandal receiving a six game suspension for accepting bribes from a booster Nevin Shapiro.

[6] Throughout his first training camp, Vernon competed against Jared Odrick, Randy Starks, Jonathan Freeny, and Jamaal Westerman for a job as a starting defensive end.

[7][8][9] Head coach Joe Philbin named Vernon a backup defensive end to begin the regular season, behind Cameron Wake and Jared Odrick.

[10] He made his professional regular season debut in the Miami Dolphins' season-opener at the Houston Texans and recorded one solo tackle in their 30–10 loss.

Vernon's first sack was alongside teammate Jared Odrick, as both of them brought Jets' quarterback Mark Sanchez down for a six-yard loss in the second quarter.

[12] On October 28, 2012, Vernon recorded a tackle and scored the first touchdown of his career after recovering a blocked punt by teammate Jimmy Wilson in the end zone during the first quarter of a 30–9 win at the New York Jets in Week 8.

[14] During training camp, Vernon competed against Jared Odrick and Dion Jordan to be a starting defensive end, opposite Cameron Wake.

Head coach Joe Philbin retained Vernon and Cameron Wake as the starting defensive ends to begin the 2014 regular season.

Head coach Joe Philbin names Vernon and Cameron Wake the starting defensive ends to begin the regular season.

On December 20, 2015, Vernon collected a season-high 11 combined tackles (six solo) and was credited with half a sack in the Dolphins' 30–14 loss at the San Diego Chargers in Week 15.

[26] On November 12, 2017, Vernon recorded four combined tackles, deflected a pass, and made his first career interception during the Giants' 31–21 loss at the San Francisco 49ers in Week 10.

[29] On January 22, 2018, the New York Giants announced their decision to hire Minnesota Vikings' offensive coordinator Pat Shurmur as their new head coach.

[31][32] Vernon entered training camp slated as a starting outside linebacker, but saw competition from Kareem Martin, Connor Barwin, and Lorenzo Carter.

[33] Head coach Pat Shumur named Vernon and Kareem Martin the starting outside linebackers to star the regular season.

[42][43] In Week 17 against the Pittsburgh Steelers, Vernon recorded his ninth sack of the season on Mason Rudolph prior to tearing his Achilles during the 24–22 win.