In 2005, Donaldson started his professional career with the Portuguese team Barreirense Basket. After playing four seasons in Spain with Ciudad de La Laguna, both in LEB-2 and LEB Oro, on July 2010 he signed for Menorca Basquet to play in the ACB League. Menorca Basquet general manager said about him, "He has improved a lot since he arrived to Spain, with a high standard of professional ethics. We hope he keeps the improvement and his contribution to many fields of the game". One season later, Donaldson returned to Iberostar Canarias. Donaldson has been named LEB Oro Most Valuable Player three times – in 2009, 2010 and 2012. On July 24, 2013, Donaldson signed with the Israeli team Bnei Herzliya for the 2013–14 season. In 28 games played for Herzliya, Donaldson averaged 10.6 points, 8.3 rebounds, 1.5 assists and 1.4 steals per game. On August 2, 2014, Donaldson signed a one-year deal with the French team ESSM Le Portel. On May 5, 2015, Donaldson signed a one-year contract extension with Le Portel. That season, Donaldson helped the team to promote to the LNB Pro A as the second seed. In his fourth season with Le Portel, Donladson helped the team to reach the 2018 FIBA Europe Cup Quarterfinals, where they eventually lost to the Bakken Bears. On September 18, 2018, Donaldson signed a one-year deal with Hapoel Be'er Sheva of the Israeli Premier League. In 36 games played for Be'er Sheva, he finished the season as the league second-leading rebounder with 9.4 per game, to go with 11.3 points, 3 assists and 1.1 steals per game. Donaldson helped Be'er Sheva reach the 2019 Israeli League Playoffs, where they eventually were eliminated by Hapoel Jerusalem in the Quarterfinals. On October 17, 2019, Donaldson returned to Bnei Herzliya for a second stint, signing a one-year deal.
