Hockey lore is full of stories about perseverance. Muzzin's is as good as any of them.

Muzzin didn't sign with the Pittsburgh Penguins after they selected him in the fifth round (No. 141) of the 2007 NHL Draft. When he re-entered the selection process for the 2009 NHL Draft, the NHL passed on him. The Nashville Predators invited Muzzin to training camp in 2009, but they cut him well before the season began.

Only when the Los Angeles Kings went to scout another player on Sault Ste. Marie of the Ontario Hockey League did Muzzin, then an overage junior player, catch their attention with his big, heavy shot and ability to get the puck out of danger. In 2009-10, he was named the OHL Defenseman of the Year and an OHL First-Team All-Star.

Muzzin made the Kings out of training camp and played his first NHL game against the Vancouver Canucks on Oct. 9, 2010. He got his first NHL point in his fourth game with an assist against the Canucks six days later.

In all, Muzzin played 11 games with the Kings in 2010-11, then spent the next season and a half in the AHL before making the Kings for the lockout-shortened 2012-13 season. Muzzin scored his first goal and had his first multipoint game in the NHL with a goal and an assist in a 4-2 win against the Phoenix Coyotes on Jan. 26, 2013. His first two-goal game and three-point performance came in a 6-4 win against the St. Louis Blues on March 5, 2013.

Among rookie defensemen, Muzzin was first with a plus-16 rating, second in goals (seven) and tied for third in points (16). He was eighth voting for the Calder Trophy, awarded to the top rookie in the NHL.

Muzzin got his first NHL postseason point in his first Stanley Cup Playoff appearance, Game 1 of the first round against St. Louis in 2013, when he assisted on the goal that sent the game to overtime (a 2-1 loss). He appeared in 17 playoff games that season and tied for the lead among rookie defensemen with three assists.

After finishing third among Kings defensemen in goals (five), assists (19), points (24) and hits (169) in 2013-14, Muzzin led NHL defensemen with six goals in the 2014 playoffs. He finished fifth among defensemen with 12 playoff points to help Los Angeles win the Stanley Cup.

Muzzin became a regular on defense in Los Angeles, finishing with at least 40 points in three of the next four seasons while averaging at least 21:39 of ice time per game. But with the Kings struggling in 2018-19, Muzzin was traded to the Toronto Maple Leafs for two prospects and a first-round pick in the 2019 NHL Draft on Jan. 28, 2019.