He gained a place on the Kenyan national team after finishing as runner-up at the Kenyan Cross Country Championships in Nairobi in February. At the 2011 IAAF World Cross Country Championships he claimed fourth place and helped the Kenyan men (including minor medallists Paul Tanui and Vincent Chepkok) to the team gold medal. Soon after he ran a half marathon best of 60:03 minutes to win at the Stramilano race. He came third at the Giro di Castelbuono 10K in July. He ran the fourth fastest time ever for the distance at the Philadelphia Half Marathon in September, completing the distance in 58:46 minutes to break Haile Gebrselassie's United States all-comers record. Kisorio made his marathon debut at the 2011 New York City Marathon in November and had a fair first performance, finishing tenth in a time of 2:10:58 hours. His last race of the year was the Saint Silvester Road Race in Brazil and he came third over the 15K distance.