[9] At the 2016 UCI Para-cycling Track World Championships in Montichiari, Italy, he finished second to fellow Australian Michael Gallagher in the Men's 4 km Individual Pursuit C5.

The two leaders were jostling for victory in their 84 km event before Dementyev, later disqualified, veered into the path of the Australian and they both crashed to the ground.

[22] At the 2017 UCI Para-cycling Track World Championships in Los Angeles, United States, Donohoe won a silver medal in the Men's Scatch Race C4-5.

[24] Donohoe won the silver medal in the Men's Scratch Race C4-5 at the 2018 UCI Para-cycling Track World Championships, Rio de Janeiro, Brazil[25] He won the gold medal in the Men's Road Race C5 at 2018 UCI Para-cycling Road World Championships, Maniago, Italy.

[29] At the 2020 UCI Para-cycling Track World Championships, Milton, Ontario, he won the gold medal in the Men's Scratch Race C5.

[30] At the 2020 Tokyo Paralympics, Donohoe won the silver medal in the Men's individual pursuit C5 with a time of 4:20.813, less than 4 seconds behind the eventual winner Dorian Foulton of France.

[35] At the 2024 UCI Para-cycling Track World Championships, Rio de Janeiro, he won the bronze medal in the Men's Scratch Race C5.

[36] Donohoe won two medals at the 2024 Paris Paralympics, silver in the Men's road time trial C5 and bronze in Mixed team sprint C1-5.