The St. Louis Blues selected Kyrou, a Toronto native, in the second round (No. 35) of the 2016 NHL Draft after his second season with Sarnia of the Ontario Hockey League.
The Blues returned Kyrou to Sarnia, where he blossomed offensively, finishing with 94 points (34 goals, 60 assists) in 2016-17 and 109 points (39 goals, 70 assists) in 2017-18. He impressed the Blues during training camp in the fall of 2018 and was on the opening-night roster when the Blues lost 5-1 to the Winnipeg Jets on Oct. 4. He scored his first NHL goal on Dec. 9, 2018. Kyrou had three points (one goal, two assists) with St. Louis and 43 points (16 goals, 27 assists) with San Antonio of the American Hockey League.