He wrote novels, but his best known work is Pod starim krovovima (Under Old Roofs), a collection of short stories in which he described the economic decline of the Croatian aristocracy. Gjalski managed to combine realism and poetry in his work because of his status as an aristocrat and his strong emotional connection to the region of Hrvatsko Zagorje. His importance in modern Croatian literature was described by the Croatian historiographer Antun Barac: "His appearance in the literature and political life of Croatia was fateful, and his work links the romantic orientation of Croatian writers of the sixties and seventies (of the 19th century) with the modern outlook of those who discovered the wider and stronger cultural life of Europe." Gjalski was heavily inspired by Ivan Sergeyevich Turgenev.
His major works are: U novom dvoru (1885), Pod starimi krovovi (1886), U noći (1887), Janko Borislavić (1887), Đurđica Agićeva (1889), Na rođenoj grudi (1890), Osvit (1892), Radmilović (1894), Za materinsku rieč (1902), Dolazak Hrvata (1924), Pronevjereni ideali (1925), etc.