Borgstrom, a skilled forward from Finland, made the jump from college to the NHL when he played for the Florida Panthers against the Ottawa Senators on March 29, 2018, three days after signing with Florida.

The Helsinki native played in four of the final seven games for the Panthers. He scored his first NHL goal in Florida's season finale, a 4-2 victory against the Boston Bruins.

The Panthers selected Borgstrom in the first round (No. 23) of the 2016 NHL Draft. He went on to a stellar two-year career at the University of Denver, where he was named the National Collegiate Hockey Conference Player of the Year in 2017-18 and was one of 10 finalists for the Hobey Baker Award, given annually to college hockey's best player. He led Denver in points (52), goals (23) and power-play points (21) and finished fourth in NCAA scoring.

In 2016-17, he led NCAA freshmen in goals (22) and finished third with 43 points in 37 games. He was named an NCAA West First Team All-America and selected as the National Collegiate Hockey Conference Rookie of the Year.

Borgstrom played with HIFK in Finland's top junior league in 2015-16, finishing with 55 points (29 goals, 26 assists) in 40 games.