Gerov became a Russian subject and came back to Koprivshtitsa, where he established his own school, named after Saints Cyril and Methodius.
In contrast to more radical revolutionary emigres who wanted an independent uprising, such as Lyuben Karavelov, Vasil Levski, and Hristo Botev, Gerov preferred to rely on Russia's support in securing Bulgaria's independence from the Ottoman Empire.
He was still suspected of having been one of the organizers of the April uprising (1876), which forced him to go into hiding and seek refuge in the Russian legation in Constantinople.
Gerov's principal work was his unique Dictionary of the Bulgarian Language (Рѣчникъ на блъгарскъıй язъıкъ).
For about fifty years, he collected, from ordinary people, a great number of words, expressions, proverbs, folk songs, and proper nouns.