He is best known for his 1938 novel Alamut, the most popular work of Slovene literature around the world, which has been translated into numerous languages.

Bartol began to be interested in philosophy, psychology, and biology, but also art, theatre, and literature, as described in his autobiographical short stories.

In Ljubljana, he met the young Slovene philosopher Klement Jug who introduced him to the works of Friedrich Nietzsche.

During World War II, he joined Slovene partisans and actively participated in the resistance movement.

Some of his works, including the 1938 novel Alamut, have been interpreted as an allegory of the TIGR and the fight against the Italian repression of the Slovene minority in Italy.