He completed his theological studies in Innsbruck. He was ordained a priest on September 30, 1912. In 1918, he passed his examination to become a religion teacher. During World War I, he was awarded the title of captain with a commemorative medal. In November 1918, János Csíz is listed in the yearbook of the Norbertinum Premontrei High School as a military chaplain: during the Aster Revolution, he took on the leadership of the civil guard and represented the Norbertinum at organizational meetings.
He arrived in the United States on July 23, 1921, aboard the steamship Paris. He served as vice president of the Hungarian Scientific Society of New York. In 1929, he had a financial dispute with the Archdiocese of New York; at that time, he is referred to as the former parish priest of Yonkers, without a specific assignment. In 1936, the capital city’s urban planning committee purchased from him the site of the playground on Donáti–Toldy Streets in what is now District I, with the intention of creating a park there. He passed away unexpectedly at the age of fifty-five.