Jun Sato was born in 1969 in Kounanku (current day Niigata City), Niigata prefecture, Japan. His father, Takashi Sato, was a member of the Japanese Lower House of Representatives and also served as the Japanese Minister of Agriculture. In 1985 Takashi Sato was awarded a United Nations Peace Medal for his contributions to the international community.

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In high school Jun Sato attended Cranbrook School in Sydney Australia. He then returned to Japan and graduated from Meikai University. Inspired by his father’s work, and with a desire to work for Japan and his local community, Jun Sato decided to follow in his father’s footsteps and become a politician.