The United Democratic Alliance party candidate had a narrow victory in the Kiambaa by-election.
Njuguna Wanjiku of UDA has won against rival Kariri Njama of Jubilee in the concluded by-elections.
According to the declaration by the IEBC at Karuri high school, Njuguna received 21,773 votes while Njama followed closely with 21,263 votes.
Although there were eight aspirants, the contest narrowed down to a two-horse race pitting Jubilee and UDA.
The announcement of results had been halted at around 3am Friday after Jubilee claimed that the election has been rigged.
The win has given UDA which is linked to Deputy President William Ruto, the bragging rights against their rival and mother party, Jubilee, whose party leader is President Uhuru Kenyatta.