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 the Central Scouting final rankings and was selected by Anaheim in the third round (87th overall) in the 2013 NHL Draft.
2013-14: Thompson skated in 26 of 42 games for the University of North Dakota as a freshman. The youngest player on the Fighting Sioux roster, he scored 3 goals with 5 assists and was +14 with 12 penalty minutes. North Dakota finished second to St. Cloud State in the newly-formed National Collegiate Hockey Conference; losing to Miami, 3-0, in the NCHC semifinals but earning an at-large bid to the NCAA Midwest Regional with a win over Western Michigan in the league’s third-place game. The Fighting Sioux defeated Wisconsin and Ferris State to win the regional; falling to Minnesota 2-1 in the Frozen Four semifinals on a goal in the game’s final second.
Thompson is a safe player in both ends of the ice. He does not play a flashy game in either the offensive or defensive sides 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. Thompson is never going to wow anyone with his skill set. He is a solid and steady two-way defenseman who reads the play a lot like a Rob Scuderi-style defenseman.
Thompson is in his sophomore season at the University of North Dakota in 2014-15. Part of a talented defense corps for one of the nation's top teams, he has gotten less acclaim than some of his more offensively-oriented teammates but has been a solid, steady presence. He is content to do a lot of the dirty jobs while others generate the attack. Long-term his lack of typical size and elite skating ability suggest it may take Thompson longer to reach the NHL level and he might take time at the minor level to achieve that goal. He projects as a lower-pairing defender.