Born in Norwood, Massachusetts, Layman was considered a "late bloomer" at King Philip Regional High School and didn't even start for his AAU team. Despite his height, he preferred to play on the perimeter. He played AAU basketball for Leo Papile with the Boston Amateur Basketball Club. As a senior, he averaged 26 points, five blocks, and four assists per game. ESPN rated him the 17th-best small forward nationally and the 3rd-best player in Massachusetts. Layman was selected as the 2012 HockomockSports.com Boys' Basketball Player of the Year. He was also chosen as the Hockomock League's Most Valuable Player for boys' basketball in 2012.
College career
Layman was recruited by Massachusetts native and then Maryland assistant basketball coach, Scott Spinelli. When he first stepped on the College Park campus, "He started 17 games and averaged 5.5 points per game as a freshman. His game initially centered around shooting 3-pointers and he even described himself as a guard. Layman gained attention for his long wavy hair, which he began growing out as a freshman. His hair even got its own Twitter account. Layman improved his averages to 11.7 points and 5.0 rebounds per game as a sophomore. He had 61 3-pointers and 27 blocks. After his sophomore year, Layman embarked on a rigorous personal training program with David Atkins and graduate assistant John Auslander to improve his strength and ballhandling. After breaking his hand in June 2014, Auslander attached Layman to Velcro pulleys to build arm muscle and used a squatting machine that did not require the use of his hands. “From the end of his sophomore year to end of his junior year, Jake improved as much as any player I’ve ever coached,” according to Mark Turgeon. Teammates described Layman as a quiet leader who led by example. Layman scored 21 points and grabbed 11 rebounds in a win at Oklahoma State on December 21. He had 23 points and 12 rebounds in a 75-59 win against Michigan State on January 17 and scored the last 10 points for the Terrapins. It resulted in him breaking out of a 5-for-23 shooting slump that spanned two games prior. As a junior, Layman was a Third-team All-Big Ten selection by the media. However, he was only an Honorable Mention All-Big Ten selection by the coaches. He was twice named Big TenPlayer of the Week. Layman was nominated for the inaugural Karl Malone Power Forward of the Year Award. Layman led Maryland to the NCAA Tournament for the first time in five years. He finished third on the team in scoring behind Melo Trimble and Dez Wells with 12.5 points per game and led the team in rebounding with 5.8 rebounds per game. Layman shot 47 percent from the field despite enduring a late season slump. After speaking with an NBA advisory committee, Layman decided to return to school for his senior season and forgo a possible second round selection in the 2015 NBA draft. As a senior, he was an Honorable Mention All-Big 10 selection by the coaches and media. Layman averaged 11.6 points and 5.3 rebounds per game, shooting 50 percent from the field and 39.6 percent from three-point range. Layman has drawn comparisons to NBA forward Chandler Parsons. Both players have the size to grab rebounds but also the shooting ability to hit 3-pointers. Of the comparison, Layman noted, “I feel like his game fits a little more in the N.B.A. than in the college game, and that’s what I feel like. I think I’m a guy that doesn’t have to have the ball in his hands all the time to really make an impact. I feel like I could be one of those guys that hangs out in the perimeter and just shoots 3s and slashes to the basket when he needs to.”
On June 23, 2016, Layman was selected by the Orlando Magic with the 47th overall pick in the 2016 NBA draft. He was subsequently traded to the Portland Trail Blazers on draft night. On July 6, he signed with the Trail Blazers and joined the team for the 2016 NBA Summer League. He made his NBA debut on November 1, 2016, scoring 17 points in eight minutes off the bench in the Trail Blazers' 127-104 loss to the Golden State Warriors. He hit five three-pointers in the game, becoming the first Trail Blazer ever to make five three-pointers in a debut, and finished one shy of the franchise record in a quarter.
Minnesota Timberwolves (2019–present)
On July 8, 2019, Layman was traded to the Minnesota Timberwolves as a part of a sign-and-trade deal in exchange for the draft rights to Bojan Dubljević.
International career
In the summer of 2012, Layman was on the under-18 United States national team that defeated Brazil for the gold medal in the FIBA Americas championship. He played more than expected due to an injury to Sam Dekker. Layman played 12 minutes per game and averaged nearly eight points and four rebounds per game. In an opening round game versus Mexico, Layman led the U.S. team in scoring with 18 points.
Personal life
Layman lives in Portland, Oregon, and has four brothers: Connor, Jimmy, Ryan and Kyle. His parents, Tim and Claire, played college sports at the University of Maine at Orono. In July 2018 Layman proposed to his long-term girlfriend, Jasmine, and were married July 20, 2019. Other members of his family reside in Carroll County, Maryland.