Presiding Judge Gusrizal Lubis said Ishaaq was guilty of violating the anti-corruption law, the money laundering law and the criminal code. He ordered Ishaaq to pay a fine of 1 billion rupiah ($84,110) or serve another year in jail.
The Prosperous Justice Party, better known as PKS, is Indonesia's largest Muslim-based party and is part of the coalition government. Agriculture Minister Suswono is a member of the party.
The same court earlier sentenced Ishaaq's aide to 14 years in jail and the two company executives to 21 months. The company's director is still awaiting trial.
Indonesia, the world's most populous Muslim nation, is plagued by graft. According to advocacy group Transparency International's corruption index, it ranked 118th out of 176 countries polled.