Born in Shewa zone, Oromia regional state of Ethiopia, Desisa made his breakthrough on to the senior international scene at road races in 2010, beginning with a sub-60-minute run for third place at the Zayed International Half Marathon in January. He engaged Wilson Kiprop in a sprint finish at the Paris Half Marathontwo months later, ending up in second place. He took to the United States road circuit and was sixth at the Crescent City Classic before taking the runner-up spot at the Cherry Blossom Ten Mile Run behind Stephen Tum. He won the Ottawa 10K in May and led an Ethiopian podium sweep with a win at the Bolder Boulder two days later. That July, he came third in a sprint for the line at the Peachtree Road Race and won the Boilermaker Road Race in Utica in a near course record time. He received his first senior international call-up for the 2010 IAAF World Half Marathon Championships. He came seventh overall, recording a time of 1:01:28 alongside his compatriot Birhanu Bekele to secure the team bronze medal for the Ethiopians. He set a new half marathon best in November at the Delhi Half Marathon and finished one second behind winner Geoffrey Mutai. He came close to a personal best at the World's Best 10K in February 2011, taking third place in a time of 28:02 minutes. This served as preparation for the City-Pier-City Loop in March, where he came out on top in a five-man sprint finish to record a personal best of 59:37 minutes for the half marathon. In a two-day period he won the Cooper River Bridge Run and then broke the course record at the Cherry Blossom 10-Miler, improving upon a mark which had stood for 16 years. That June he reached the podium at the World 10K Bangalore, coming third behind Kenyan opposition. He was not selected for the World Championships that year, but instead won the half marathon at the 2011 All-Africa Games held that same month. In November he returned to Delhi and ran a best of 59:30 minutes to win the half marathon race, beating Geoffrey Kipsang by a second. In June 2012 he ran a personal best of 27:18.17 minutes to win the 10,000 metres in Liège. He was selected as an Olympic squad reserve as a result. A 5000 metres best of 13:22.91 minutes came in June, but ultimately he did not compete at the Olympics. He tried to defend his title at the Delhi Half Marathon but managed only seventh place. In his debut over the marathon distance, he made one of the fastest ever debuts by winning the 2013 Dubai Marathon in a time of 2:04:45 hours. He was surprised by the quick time and said he would like to make a world record attempt in the future. Three months later, in the 2013 Boston Marathon, he took the victory in a time of 2:10:22. Desisa was not hurt in the Boston Marathon bombing that occurred after his victory because the bombing took place nearly 3 hours after he passed through the finish line. Desisa later, in a widely acclaimed gesture, returned his 2013 Boston Marathon winner medal back to the city, in order to honor the victims of the bombings. as they pass mile 19 during the 2016 Boston Marathon, but Hayle went on to win; Desisa came in second. Desisa won the 2015 Boston Marathon on 20 April 2015 with a time of 2:09:17. He came in second in 2016 to fellow Ethiopian Lemi Berhanu Hayle. On 6 May 2017, Desisa participated in Nike's Breaking2 attempt to run a sub-2-hour marathon. Desisa held on up until around kilometer 18, when he began to slow and fell off the projected sub-2-hour pace. Eliud Kipchoge won the race in 2:00:25, and Tadese was second in 2:06:51, and Desisa was third with time of 2:14:10. Although Desisa was way far off from actually breaking the barrier, former athlete and world record holder Paula Radcliffe said "He is still very young, at only 27... Once he figures it all out and matures a bit more, he will be unstoppable". Desisa won the 2018 New York City Marathon on 4 November 2018 with a time of 2:05:59. On 5 October 2019, Desisa became the World champion in men's marathon by running a season's best of 2:10:40 at the 2019 World Athletics Championships in Doha.
