Smith grew up playing hockey in Des Moines before moving with his family to Minnesota when he was 14.[1]
He played college hockey for UMass Lowell of Hockey East for three seasons while majoring in chemistry.[2]
In his freshman season at UMass, Smith was named to the All Hockey East Rookie Team after he led the team with 16 goals, 19 assists for a total of 35 points. He also became the first River Hawk rookie since Scott Wilson in 2011 to score 30 points in a season.[3] On April 21, Smith and Zack Kamrass were awarded the UMass Lowell Hockey Most Valuable Player Award. Smith was also awarded the River Hawks Rookie of the Year.[4]
In his sophomore year, Smith was named to the Hockey East All-Tournament Team and won the River Hawks leading scorer award.[2] He recorded his first career hat trick in an 8–1 win over Arizona State on January 30, 2016.[5] In the 2016 Hockey East Men's Ice Hockey Tournament, Smith helped Massachusetts–Lowell beat Boston University in the Quarterfinals to advance to the Semifinals and eventually the Championship.[2] UMass lost in the Championship match against Northeastern 3–2.[6]
In his junior year, Smith was named a semi-finalist for the Walter Brown Award as the best American-born college hockey player in New England.[7] The River Hawks won the 2017 Hockey East Men's Ice Hockey Tournament and Smith was named to the All Tournament Team and Tournament MVP.[8] On March 29, 2017, Smith chose to forgo his senior year at UMass and signed as an undrafted free agent by the National Hockey League's Buffalo Sabres.[9]
Professional
C. J. Smith during the 2022 Calder Cup Finals
Smith made his Sabres debut on April 2, 2017 in a 4–2 loss to the New York Islanders, in which he also got his first NHL point with an assist on a goal by Evander Kane.[10] When Smith made his debut, he became one of only two players in league history to have been born in the state of Iowa, joining goaltender Scott Clemmensen.[11]
Smith began the following season with the Rochester Americans after being cut from the Sabres training camp.[14] On January 8, 2019, Smith scored his first NHL goal in the second period against the New Jersey Devils.[15]
As a free agent after five seasons within the Sabres organization, Smith was signed to a one-year, two-way contract with the Carolina Hurricanes on July 28, 2021.[16]
On August 2, 2022, Smith was signed as a free agent to a one-year, two-way contract with the New York Rangers.[17]
On November 20, 2023, Smith signed a one-year contract with JYP Jyväskylä of the Finnish Liiga.[18]