Continuing to play with Dexter, Donato made his junior debut with the South Shore Kings in the United States Premier Hockey League before finishing with the Omaha Lancers of the United States Hockey League, having committed to a collegiate career with Harvard University, in following his father's footsteps who was now the Crimson's head coach.

[4] Having led the Crimson as a junior in scoring through the 2017–18 season with 26 goals and 17 assists for 43 points in just 29 games, Donato opted to leave the college early and turn professional.

[5][6] Despite leaving college hockey, Donato was still enrolled in Harvard classes and was aiming to finish the semester while playing in the NHL.

[12][non-primary source needed] On February 20, 2019, Donato and a 2019 conditional fifth-round pick were traded to the Minnesota Wild in exchange for Charlie Coyle.

[17] On September 12, 2021, the expansion team Seattle Kraken signed Donato as a free agent to a one-year, $750,000 contract for the 2021–22 season.

[19] He followed that up with the first official goal in Seattle Kraken franchise history, scoring on opening night in a 4–3 loss to the Vegas Golden Knights on October 12, 2021.

[3] Donato scored a career-high 16 goals and added 15 assists for 31 points in 74 games, as Seattle missed the playoffs in their inaugural season.