Following a highly successful career as an academic linguist, he devoted himself to missionary work on behalf of the Russian Orthodox Church.

Based around his view that mother tongue instruction was the key factor in ensuring that animists, he developed the Ilminsky Method.

[1] Ilminsky is also described by Nicholas Zernov as being a major contributor to translations of the Bible to many Asiatic languages.

Nicholas also comments that Ilmisky could speak Arabic, Persian, Turkish, Tatar, Cheremis, Chuvash, Kirgiz, Mordvin, Yakut and more Asiatic languages.

[2] He worked closely with the educator Ilya Ulyanov and his model of education, described as "national in form, Orthodox in content" can be considered an influence on Ulyanov's son Vladimir Lenin who developed an approach which was described as "national in form, socialist in content".