Los Angeles Kings Martinez was drafted 95th overall by the
Los Angeles Kings in the
2007 NHL entry draft while playing for
Miami University. He made his professional debut for the Kings'
American Hockey League (AHL) minor league affiliate, the
Manchester Monarchs, in 2008. A year later, he was announced to the opening roster for the
2009–10 season with Kings, in which he played four games and had no goals and no assists on six shots on goal. He was sent back down to the Manchester Monarchs for the first 20 games of the
2010–11 season. On November 23, 2010, he was recalled by the Los Angeles Kings to replace the struggling
Jake Muzzin. On November 24, Martinez scored his first NHL goal, on the power play, in 4–1 loss to the
Montreal Canadiens at the
Bell Centre against goaltender
Carey Price. Martinez had his first multi-point game December 4, 2010, including a goal against
Chris Osgood of the
Detroit Red Wings in a 3–2 victory for the Kings. After joining the squad for the 2010–11 season, Martinez earned trust from former Kings Head Coach
Terry Murray for solid offensive and defensive play, and that continued after
Darryl Sutter replaced Murray in December 2011. On July 8, 2011, Martinez signed a two-year, $1,475,000 contract with the Kings. On June 11, 2012, the team won the
Stanley Cup. With the
2012–13 NHL season being threatened by
a lockout that ultimately wiped out half the season, on December 31, 2012, Martinez signed with the
Allen Americans of the
Central Hockey League. He played with them until the end of the lockout. Martinez was injured for 10 of the Kings' first 15 games of the
2013–14 season, but wound up returning as a regular on the Kings' defense, even contributing to the team's offense. He scored two series winners en route to the Kings' second
Stanley Cup title – on June 1, 2014, Martinez scored 5:47 into overtime of Game 7 of the Western Conference Finals against the
Chicago Blackhawks on goaltender
Corey Crawford; 12 days later, in Game 5 of the
2014 Stanley Cup Final against the
New York Rangers, a shot by
Tyler Toffoli, which rebounded off goaltender
Henrik Lundqvist in double overtime, led to another Martinez goal. The goal was scored with 5:17 left in double overtime as he became the 17th player to
score the Cup-winning goal in overtime. He became the first to do it since
Patrick Kane in 2010 and the first to do it at home since
Bob Nystrom in 1980. On December 4, 2014, Martinez signed a 6 year $24 million extension with the Kings. Playing a full 82 games for the only time in his NHL career (and one of only four defensemen on the team’s roster), Martinez recorded a career high 39 points in the
2016–17 season, his best season post-Stanley Cup Final.
Vegas Golden Knights On February 19, 2020, Martinez was traded to the
Vegas Golden Knights in exchange for a second-round pick in the
2020 and
St. Louis' second-round pick in the
2021 NHL entry draft. Martinez had a successful debut with the Golden Knights, scoring a goal and an assist in a 5–3 win over the
Tampa Bay Lightning. On July 28, 2021, Martinez signed a three-year, $15.75 million contract with the Golden Knights. On November 11, 2021, Martinez was cut in the face by
Brandon Duhaime's skate in a match against the
Minnesota Wild. He would be placed on long term injured reserve as a result. He was activated off the IR on March 26, 2022. During the
2023 Stanley Cup Final against the
Florida Panthers, Martinez scored two goals, after going scoreless most of the playoffs, to secure his third Stanley Cup championship. After hoisting the Cup himself, he handed it to former Kings teammate
Jonathan Quick, who had joined the Golden Knights earlier in the year. Reflecting on his third victory, Martinez said "this one is a little different being on the other side of the age spectrum."
Chicago Blackhawks Leaving the Golden Knights as a free agent, Martinez signed a one-year, $4 million contract with the
Chicago Blackhawks on July 1, 2024. On April 13, 2025, shortly before the Blackhawks' last home game of the season, Martinez announced that he would be retiring from the NHL, forgoing the Blackhawks' two remaining road games. Martinez, alongside fellow retiree
Patrick Maroon, received a video tribute and standing ovation during the game, as well as a handshake line from the visiting
Winnipeg Jets. ==International play==