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 nominally orthodox believers could become more committed to these beliefs, he developed the Ilminsky Method.
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".
- Kreindler, Isabelle. "Nikolai Ivanovich Ilminsky". The Gale Group. Retrieved 20 March 2015.
- Профессор Н.И.Егоров. Выступление на чувашском языке (Круглый стол, посвященный к 195-летию со дня рождения Н.И. Ильминского, 120-летию Н.Н. Поппе и 145-летию К.П. Прокопьева). Чăвашла.
- Сергей Щербаков: Миссионерско-просветительская система Н.И. Ильминского и чуваши: две стороны одной медали
- Agabazar: Сумбур вместо гармонии