During his time at Canyon del Oro, he was named to the PrepStar All-West Region Team, and was also a Two-Time Defensive Player of the year.

[1] As a true freshman with the Stanford Cardinal in 2012, Martinez played in fourteen games and had the first tackle of his college career against Duke University.

His best game of the year coming against the rival California Golden Bears where he had six tackles, forced a fumble, and had his first career interception.

[1][9] On December 22, 2015, it was announced that Martinez was one of four Stanford players who had accepted their invitation to play in the Senior Bowl, along with Kevin Hogan, Joshua Garnett, and Kyle Murphy.

[10] On January 30, 2016, Martinez played in the Senior Bowl as part of Dallas Cowboys head coach Jason Garrett's South team that lost 27–16 to the North.

[12] On March 17, 2016, Martinez attended Stanford's pro day and opted to stand on the majority of his combine numbers and only performed the 60-yard shuttle, vertical jump (34"), and positional drills.

[14][15] At the conclusion of the pre-draft process, he was projected to be a fourth to sixth round pick by NFL draft experts and scouts.

He received first team reps due to Sam Barrington's absence after suffering a foot injury a year prior.

Throughout training camp, he competed for a job at inside linebacker against Sam Barrington, Carl Bradford, and Joe Thomas.

[27] The nickname is a play on "Shake and Bake", a catchphrase of popularized by the film Talladega Nights: The Ballad of Ricky Bobby.

[29] He made his first career start and professional regular season debut in the Packers' season-opener at the Jacksonville Jaguars and recorded six combined tackles in their 27–23 victory.

[30] On October 20, 2016, he recorded five combined tackles, two pass break ups, and made his first career interception off Matt Barkley during a 26–10 win against the Chicago Bears.

[33] He finished his rookie season in 2016 with a total of 69 combined tackles (47 solo), four pass deflections, a sack, and an interception in 13 games and nine starts.

Martinez, Ryan, Matthews, and Perry returned as the starting linebacker corps under defensive coordinator Dom Capers to begin the 2017 regular season.

On November 26, 2017, he made 15 combined tackles, broke up a pass, and intercepted Ben Roethlisberger during a 31–28 loss at the Pittsburgh Steelers.

On December 3, 2018, the Packers announced their decision to fire head coach Mike McCarthy after a 20–17 loss against the Arizona Cardinals brought them to a 4–7 record.

[45] In week 7 against the Oakland Raiders, Martinez made a team high 16 tackles and forced Derek Carr to fumble the football into the end zone, causing a touchback, in a 42–24 win.

[56] On November 10, 2022, Martinez announced his retirement from professional football after seven seasons,[57] reportedly after he sold a rare Pokémon card.

[60] In August 2023, Martinez's Pokémon stream on the Whatnot platform was accused of scamming buyers by rigging casino-like games.