Businessman Charles Kibiru is set to be the only independent senator after Kirinyaga voters chose him over Jubilee candidate.
It is also the first time voters in the county defied the six-piece voting call since the introduction of multi-party in 1992.
Mr Kibiru, a newcomer in politics, was declared the winner after trouncing three of his opponents among them, the incumbent Daniel Karaba of Jubilee.
He garnered 147,921 votes against Mr Karaba's 130,925 votes.
Narc Kenya candidate Dishon Kirima got 9,897 votes while Mr James Karimi who was also vying as an independent candidate, managed to get, 11,987 votes.
Mr Kibiru had participated in the Jubilee nominations but he lost to Mr Karaba with a narrow margin.
County Returning Officer Samuel Seki presented a certificate to Mr Kibiru shortly after 1am Friday.
Mr Kibiru thanked the residents for electing him.
"This is a historic moment for me. Despite all odds and the fact that I was an independent candidate I have triumphed. For the first time in the history of the region people defied those telling them to vote only for Jubilee candidates," he said.
He promised to keep governors on toes to ensure they deliver.
"I will effectively carryout my oversight roles without fear or favour. The residents have done me proud and I must serve them well. All projects which can benefit the residents must be fully implemented and without delay," said Mr Kibiru.
Mr Kibiru also said he will embark on bringing the local leaders together for the sake of development.
"Leaders had been divided for decades but it is time for them to unite. We should shun retrogressive politics and come together so that we can serve our people some who are living below poverty line," said Mr Kibiru.