2009-10: Keaton Thompson played for Devils Lake High School in North Dakota. In 24 games he scored 7 goals with 11 assists and had 20 penalty minutes.
2010-11: Thompson played in the USHL as a 15-year-old and skated for Team Great Plains in the Upper Midwest Elite High School League in the fall before playing his junior season at Devils Lake HS. He played 15 games for Fargo, including two playoff games, and was scoreless with 9 penalty minutes. He had 3 assists with 16 penalty minutes in 19 games for Great Plains and scored 9 goals with 29 assists in 24 games and had 58 penalty minutes for Devils Lake. Thompson was invited to USA Hockey's Select 16 Development Camp in July and committed to playing college hockey at the University of North Dakota.
2011-12: Thompson moved to Ann Arbor to play for the USA National Team Development Program's U17 team. The second-leading scorer amongst defensemen, he scored 5 goals with 17 assists and had 33 penalty minutes in 54 games. In four games at the 2011 Four Nations Tournament in Russia he scored 1 goal with 2 assists as the USA finished first. The USA was second in the 2012 U17 World Hockey Challenge and Thompson had 3 assists with 4 penalty minutes in five games. The USA U17 team finished first in the Vlad Dzurilla U18 tournament and Thompson had 1 assist in three games.
2012-13: Thompson returned to Ann Arbor to play for the NDTP's U18 squad and won a silver medal for the USA at the 2013 U18 World Junior Championship. He played 67 games and scored 4 goals with 18 assists and 40 penalty minutes. Thompson had an up-and-down tournament at the WJC, finishing -2 with 1 assist in seven games. Thompson was ranked 53rd amongst North American skaters in Central Scouting's final rankings prior to the 2013 NHL Draft.
Thompson is a safe player in both ends of the ice. He does not have high-end talent in either the offensive side of the game or the defensive side of the game but can play intelligently and capably in both regards. He makes strong decisions with the puck and is rarely out of position. Reads a lot like a Rob Scuderi style defenseman with his size and skill set.
Thompson is never going to wow anyone with his skill set. However, he is a solid and steady two-way defenseman who projects as a fifth or sixth blueliner at the NHL. He starts his career with a top-level program at the University of North Dakota in 2013-14.