[1] He graduated from the University of Ljubljana's Faculty of Economics in 1959 and then taught and worked as a school principal.
In 1978 he became the vice-president of the Executive Council of the Assembly of the Socialist Republic of Slovenia, and in May 1984 its president.
[1][2] Šinigoj served as the president of the Executive Council of the Socialist Republic of Slovenia from May 23, 1984, to May 16, 1990.
He was preceded by Janez Zemljarič and succeeded by Lojze Peterle following the first direct multiparty elections held in Slovenia since World War II.
[1][2] After handing over government affairs to Lojze Peterle, Šinigoj was the director of a bank in Nova Gorica until 1993.