At the
2010 IAAF World Cross Country Championships held in Bydgoszcz, Poland, Hawkins finished 47th in the
junior men's race in a time of 24 minutes and 21 seconds. In 2013 he finished seventh in the men's under-23's race at the
European Cross Country Championships. At the
2014 European Cross Country Championships he improved to a fifth-place finish in the under-23's race. In October 2015 he finished the
Great Scottish Run in a time of one hour two minutes and 42 seconds, setting a personal best to in second place overall behind Uganda's
Moses Kipsiro and winning the gold medal for Scottish athletes. Later that month he competed in his first marathon in
Frankfurt, finishing twelfth in two hours 12 minutes and 17 seconds, in a race won by Ethiopia's
Sisay Lemma. At the
2016 London Marathon, his second event over the distance, Hawkins finished eighth overall, and was the first British-qualified athlete to finish, in a time of two hours 10 minutes and 52 seconds. This time was inside the qualifying time of two hours 14 minutes needed to earn him a place in the
Great Britain team for the
2016 Summer Olympics to be held in Rio de Janeiro, Brazil. He was joined in the
men's marathon by fellow British athletes,
Tsegai Tewelde and his brother Derek Hawkins. Hawkins finished ninth in the
marathon at the
2016 Olympics in a time of 2:11:52. In January 2017 he became the first British athlete to beat
Mo Farah in any race for 7 years at the
Great Edinburgh International Cross Country race, which has been held annually since 2005. In fact Callum was 2nd in this race overall (with Farah in 7th) - Callum had put in a strong performance to lead for most of the race, but was out-sprinted by
Leonard Korir in the final straight. In February 2017 Hawkins won the
Kagawa Marugame Half Marathon in Japan, in 60:00, setting a new Scottish half-marathon record. The previous record was set by
Allister Hutton in 1987. In August 2017 Hawkins finished 4th in the
men's marathon at the
2017 World Championships, equalling the best ever performance by a British runner in this event. Hawkins competed at the
2018 Commonwealth Games held in
Gold Coast, Australia, and collapsed near the finish while leading, from heat exhaustion in 30 degree heat. Hawkins came fourth in the
men's marathon at the
2019 World Athletics Championships, the same placing as in 2017. He competed in the
men's marathon at the
2020 Summer Olympics in Tokyo, Japan. ==International competitions==