Cobb was drafted in the 2nd round (64th overall) of the 2011 NFL Draft by the Green Bay Packers. On September 8, 2011, in the Packers' opening game of the season against the New Orleans Saints, Cobb became the first person born in the 1990s to play in the NFL. Cobb recorded his first NFL touchdown on a 32-yard reception in the first quarter, and followed up with a 108 yard kickoff return in the third quarter that tied the record set by Ellis Hobbs of the New England Patriots, in 2007 for longest kickoff return in NFL history, and was later named Play of the Year at the season-ending NFL Honors banquet. In a Monday night game against the Minnesota Vikings on November 14, Cobb scored his second special teams touchdown of the year on an 80 yard punt return in the first quarter. With that, Cobb became the first rookie in Packers history to return both a kick and a punt for a touchdown in the same season.


NFL records
Longest kickoff return touchdown in a single game: 108 (2011) (tied with Ellis Hobbs)