During his time in the senate, he formed the Sonko Rescue Team, an officially registered Non-Governmental Organization that provided government-like services to residents of Nairobi slums. The then governor of Nairobi County, Dr. Evans Kidero opposed the activities of the group, citing conflict of interests with the county government’s operations. The Senator acquiesced and donated the vehicles to the county government after several weeks of tense public exchanges.
In January 2016, Mike Sonko had announced his intentions to run for Governor of Nairobi County in the Kenyan general election, 2017. After a grueling primary campaign against Peter Kenneth, Sonko run for the Gubernatorial seat for Nairobi County with the Jubilee Party of Kenya and defeated the incumbent Evans Kidero to become the second Governor of Nairobi.