Kalac became a priest in Pazin in 1875 and was a chaplain there until 1882. He supported the Croatian people through his work and came into conflict with Italian political supporters. Since the diocese of Trieste, which at that time included Pazin and other parts of central Istria, was headed by the Istrian revivalist Bishop Juraj Dobrila, Kalac was able to continue his work in the region. In 1882, he was transferred to Buzet as pastor and dean. In 1906, he returned to Pazin and took an appointment as prefect and dean. His Croatian revivalist work was well-received. He promoted Croatian education and defended the national rights of Croats in Istria. As a result of his work, he was constantly attacked by the ruling elite.[3][1][2]
Kalac was well known for his position as a defender and protector of the Croatian national spirit during the Italianization of Istria. Because he was a high-ranking priest within the Catholic Church, he did not hold the most prominent positions in civic associations, but his contribution to these circles was still significant.[3][2]
Kalac also contributed to the development of Croatian poetic expression in Istria during the 19th and 20th centuries. He published about a hundred songs in Naša sloga, often under the pseudonym Nadan Zorin. He also published prose and wrote plays. His songs reflected his commitment to Croatia;[2][3] one song in particular, "Predobri Bože", was once considered the anthem of Istrian Croats. He translated literary works from various languages into Croatian, including Schiller's "Song of the Bell" and Virgil's Eclogues.
He was also the editor of a memorial book published on the 100th anniversary (1912) of the birth of the Croatian revivalist Bishop Juraj Dobrila.
Kalac died on 13 May 1919 in Pazin.[3]
