In 1856, he graduated from the Nersisian School of Tiflis (Tbilisi), where, according to Sergey Sarinian, his patriotic-democratic views formed under the influence of educator Petros Shanshian.

After studying for one year at Tiflis's state gymnasium, Proshian returned to Ashtarak in 1857 and was appointed inspector of the parish school.

He actively participated in the founding of the Armenian professional theater and in the establishment of girls' schools in Tbilisi, Shusha, Agulis, Astrakhan and elsewhere.

From 1879, he was invited to Etchmiadzin and was appointed inspector of the Armenian religious schools of the dioceses of Erivan and Kars.

He also translated foreign-language works into Armenian, including Charles Dickens's David Copperfield, Leo Tolstoy's Childhood and Boyhood, and Eliza Orzeszkowa's Przygoda Jasia.