In 1966 he went into politics and stopped working as a lawyer. He was elected to the municipal council of Rotterdam and at the same time he was made alderman concerning infrastructure and public works. In 1974 he resigned his position as alderman after a conflict concerning funding for the airport of Zestienhoven. The municipal council held him responsible for the airport, but refused to provide him with the money to buy a firetruck. Polak felt that without the firetruck he could not provide the safety that was needed and therefore chose to resign. He did however continue on as a member of the municipal council for another two years. Shortly after resigning as alderman he took up the position of President of the Board of the Erasmus University Rotterdam, the same university his father was once rector of. Two years into his presidency he was elected to the Senate, and two weeks after becoming a member of that institution his membership of the municipal council of Rotterdam ended. Polak would serve for just over one year as senator, until September 1977.
