At the 2012 Summer Olympics in London at the age of 19, he competed in the finals of the Men's 400 m race, placing eighth with a time of 45.14, after running a time of 44.97 in the semifinals. Two and a half years prior, Solomon had never run a 400m race. He was the first Australian man in 24 years to reach the 400m final at the Olympics. He also ran on Australia's 4x400 relay team that ran 3:03.17 in the first round, and did not advance to the final. He won the 2012 Australia National Championship in the 400m in a time of 45.54, despite his hamstring injury. At the 2012 IAAF World Junior Championships in Barcelona, Spain, he won a bronze medal in the 400m as he set a personal record of 45.52. He was awarded the 2012 Richard Coombes Memorial Award for Most Outstanding Male Athlete.