The Court of Appeal overruled Justice Joseph Sergon's decision to nullify the election.
Justice Mohamed Warsame, in a decision by the three-judge bench presiding over the case, said the High court's reasons for nullifying the poll was not founded in law.
"Babu Owino was validly elected as Embakasi East MP," the judge said in the judgement issued at the Supreme Court buildings on Friday.
The court said it was not satisfied with the nullification of the learned judge and has allowed the judgement to be set aside.
The outspoken former student leader also announced that he is ready to work together with his opponents in a bid to build his constituency.
Flanked by a number of Nairobi leaders, Babu also vowed to fight corruption and make sure those involved in graft in the country are dealt with.