Randall Sr. worked at the Denso car parts factory in Maryville, Tennessee and also worked side jobs in the evenings, ranging from installing ceramic tile floors to mowing lawns and plowing snow, with young Randall II helping.

[3] At that time, he played both offense and defense as well as special teams but made his biggest impact as quarterback for the Tornadoes.

He finished third in the state meet in the 100-meter dash his senior year, recording a career-best time of 10.75 seconds.

He also helped lead the Alcoa 4 × 100 m relay squad to a second-place finish in the state meet as a junior.

He was also the first player to score a rushing, passing, and receiving touchdown in the same game for Kentucky since Shane Boyd in 2003.

[20] 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.

[23][24] In a Monday Night Football 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.

[26] In 2013, Cobb was limited to six games (including four starts) due to a broken fibula injury suffered in Week 6 against the Baltimore Ravens.

He caught a memorable 48-yard game-winning touchdown pass from Aaron Rodgers late in the fourth quarter to win the NFC North title for the Packers.

I knew I had a good thing going for me, and still I signed a pretty lucrative deal that I can handle as far as making that last for the rest of my life.

[53] In Week 13, during the "Miracle in Motown" win, Cobb recovered a James Starks fumble to give the Packers their first touchdown of the game to make the score 20–7 in favor of the Detroit Lions.

[55] In the Wild Card Round against the Washington Redskins, Cobb scored a receiving touchdown in the 35–18 victory.

[56] On September 16, 2016, Cobb was fined $9,115 for pulling the face mask of linebacker Paul Posluszny in Week 1 against the Jacksonville Jaguars.

[58] In the Wild Card Round against the Giants, Cobb had five receptions for 116 yards and three touchdowns, including catching a 42-yard Hail Mary from Aaron Rodgers at the end of the second quarter.

[59] [60] In the 2017 season, Cobb finished with 66 receptions for 653 yards and four touchdowns despite losing starting quarterback Aaron Rodgers.

He recorded a career-long 75-yard touchdown reception late in the fourth quarter to give the Packers the go-ahead score in the 24–23 victory.

[67] Cobb caught his first touchdown with the Cowboys in the first week of the 2019 season with 9:48 left in the third quarter in their home opener against the Giants.

[68] In Week 10 against the Vikings on Sunday Night Football, Cobb caught six passes for 106 yards and a touchdown in the 28–24 loss.

[69] During Week 11 against the Lions, Cobb finished with four receptions for 115 receiving yards and a touchdown as the Cowboys won 35–27.

In Week 3 against the Pittsburgh Steelers, Cobb caught four passes for 95 yards and his first touchdown reception as a Texan during the 28–21 loss.

[77] On July 28, 2021, the Packers traded for Cobb at the request of his close friend and former teammate, Aaron Rodgers.

[78] Houston traded the rights to Cobb – and most of his salary obligations – to the Packers in exchange for a sixth-round draft pick.

[79] He sustained an injury on a touchdown catch during a Week 12 win over the Los Angeles Rams, and was deemed questionable to return to the game.

[80] Head coach Matt LaFleur announced on January 19 that he had been cleared to return for the Packers' Divisional Round playoff game against the San Francisco 49ers where they lost on a last second field goal.