His dismissal has been declared unlawful.
The South Gauteng High Court in Johannesburg found that he should return to his position with immediate effect.
Moyo was suspended in May and later fired as CEO of the JSE listed insurer.
The company said this was due to a conflict of interest in his personal business matters.
It later emerged that Moyo is also the co-founder of NMT Capital, a boutique investment company.
Old Mutual claimed he allowed dividends owed to the company as a preferential shareholder and institutional investor to slide into arrears while he received a R30-million payout.
Tuesday's judgement is the first part of Moyo's legal battle against Old Mutual.
READ: Old Mutual CEO suspended
Moyo is seeking an order from the South Gauteng High Court to declare chairman Trevor Manuel a delinquent director under the Companies Act.
Moyo alleges that Manuel treated him with open hostility after his objection to the board over the payments of Manuel's legal fees, amounting to millions of rand in his legal battles relating to the Guptas.