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 Marathon two 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 (59:39 minutes) in November at the Delhi Half Marathon and finished one second behind winner Geoffrey Mutai.