Donnelly qualified to compete in the men's welterweight event at the 2016 Summer Olympics to be held in Rio de Janeiro, Brazil, via his fourth-place ranking in the World Series of Boxing. Only the top two ranked athletes were due to qualify through the rankings but two of the athletes ranked ahead of him qualified by alternate methods, Morocco’s Mohammad Rabii secured his place through the 2015 AIBA World Boxing Championships and Andrey Zamkovoy won the Russian championships to confirm his place.