His father, Ignác Proszt, was a cantor and teacher; his mother’s name was Vilmá Varga. His brother became a Carmelite monk. János Proszt, SDB (Sármellék, May 5, 1908 – Montevideo, Uruguay, July 24, 1983) was a Hungarian Salesian priest, missionary, and pastor to the Hungarian émigré community in South America. His father was Ignác Proszt, a cantor and teacher; his mother was Vilma Varga. He was raised in a religious family, where the idea of pursuing a priestly vocation arose even during his childhood. He originally intended to become a Salesian brother, so he learned the shoemaking trade in Keszthely, and then on May 20, 1927, he entered the Clarisseum in Rákospalota. He began his novitiate in August, took the habit on December 8, and made his first religious vows on August 15, 1928. His superiors saw in him a calling to the priesthood, so he pursued theological studies and was ordained a priest on November 27, 1938, in Córdoba, Argentina.

Even as a young religious, he volunteered for missionary work and was sent to Argentina in 1931. He arrived in Patagonia on November 6, where he began his ministry in the Salesian missions. He worked for more than thirty years in the Salesian Works in Patagonia, primarily providing pastoral care to indigenous peoples and the faithful living in isolated communities. Although few details of this period have survived due to his modest nature, his memoirs reveal that he considered this to be the most beautiful and fruitful period of his life. He took particular delight in preserving the traditions of the Patagonian missions and venerating Ceferino Namuncurá, who was of indigenous descent.

On March 11, 1962, at the behest of his superiors, he was transferred to Uruguay, where he continued his ministry as a Hungarian pastor (missionarius cum cura animarum) appointed by the Holy See, based in Montevideo. He also worked briefly in Brazil before returning to serve in Montevideo. During his nearly twenty years in Uruguay, he conducted more than three hundred Hungarian funerals, while recording only 106 baptisms, which clearly illustrates the aging of the émigré community. In his letters, he wrote repeatedly about the fate of the dwindling Hungarian community and his concern that no Hungarian priest would remain in the country after his departure.

In the final years of his life, his health deteriorated significantly: he suffered from heart disease, his eyesight had severely weakened, and he spent extended periods in a sanatorium on several occasions. Nevertheless, he continued to serve his congregation to the best of his ability. In 1981, he even attended the 50th-anniversary reunion in Argentina of the class with which he had once arrived on a mission to Patagonia. In his final letter, he bid farewell to his acquaintances, writing that by the time his words reached them, he hoped to already be “at home” in the eternal homeland. He passed away on July 24, 1983, in Montevideo. He dedicated his entire life to the spirituality of Don Bosco, to missionary service, and to the pastoral care of the Hungarian community in South America.

Kéziratban megőrzött emlékei épületes olvasmány saját gyermekkoráról és epizódokban bemutatott nevelői tapasztalatáról.