The 22-year-old defenseman, an undrafted free agent, had 25 points (seven goals, 18 assists) in 33 games for St. Cloud State University this season, when he was captain. He had 34 points (six goals, 28 assists) in 39 games in 2018-19.
"I am very humbled and excited to join the Boston Bruins organization; it is truly a dream come true for me and my family," Ahcan wrote on Twitter. "When the time is right, I look forward to getting started with my new teammates."
Ahcan (5-foot-8, 185 pounds) had one assist in seven games for the United States at the 2017 IIHF World Junior Championship. Bruins defenseman Charlie McAvoy was a teammate on the tournament winners.
