After completing his collegiate career, Scrivens had not been selected in the National Hockey League (NHL) Entry Draft, making him an unrestricted free agent, able to sign with any team in the league. The Toronto Maple Leafs signed Scrivens to a one-year contract on April 28, 2010. Scrivens’ decision to sign with the Leafs was largely due to the presence of goaltending coach François Allaire, whom Scrivens had worked with during an off-season goalie camp.

Scrivens started the 2010–11 season with the Reading Royals of the ECHL, the Maple Leafs’ second tier affiliate. He played in 13 games with the Royals, winning 10. For his efforts he was selected to represent the Royals in the ECHL All-Star Classic. His strong play at the ECHL level, and injuries to other goalies in the Maple Leafs systems, earned Scrivens two separate callups to the Toronto Marlies of the American Hockey League (AHL), one in November and one in February. Scrivens was one of two goalies on the Marlies Clear Day roster announced on March 8, 2011, meaning he would be spending the remainder of the season at the AHL level, barring injury or suspension.

The Maple Leafs re-signed Scrivens on July 1, 2011. He was called up to the NHL as of October 24, 2011, in an emergency situation. After serving as backup for the previous games, he made his first regular season start on November 3, 2011, in Columbus against the Blue Jackets. In that game, he recorded his first career win and stopped 38 shots in a 4–1 game. As the NHL resumed play after the 2012–13 NHL lockout, Scrivens became a full-time NHL goaltender for the first time, serving as the backup to James Reimer, starting Toronto’s first two games. Scrivens recorded his first NHL career shutout February 16, 2013, in a 3–0 victory over the Ottawa Senators.

Scrivens was traded to the Los Angeles Kings in June 2013 along with Matt Frattin and a second round pick in exchange for goaltender Jonathan Bernier. Scrivens served as the backup goaltender to Jonathan Quick.

On January 29, 2014, Scrivens set the NHL record for most saves by a goaltender in a regular season shutout, stopping 59 shots from the San Jose Sharks during 60 minutes of regulation time, leading the Oilers to a 3–0 victory. Scrivens also set an Oilers franchise record in the process for most saves in a game, surpassing the previous record of 56 set by Bill Ranford in 1993.

The Oilers re-signed Scrivens to a two-year contract worth $2.3 million per season on March 3, 2014.

On December 28, 2015, the Montreal Canadiens announced that they had acquired Scrivens from the Edmonton Oilers, in exchange for forward Zack Kassian.

On July 14, 2016, Scrivens agreed to a one-year contract with HC Dinamo Minsk of the Kontinental Hockey League (KHL) for the 2016-2017 season. He played for Salavat Yulaev Ufa in the 2017-2018 season after which he announced his retirement.

On September 9, 2018, Scrivens announced he would be managing the University of Denver’s men’s hockey team.