Considered a renowned patriot,[3] Kukuljević was a proponent of Illyrian movement and avid collector of historical documents, primarily those for his work in Croatian historiography and bibliography.

In the first period, he was a partisan of the liberation of Croatia from Austria and Hungary, an uncompromising ideologue promoting revolutionary actions to achieve the unity of the South Slavs.

Believing that the South Slavs can be delivered and unified only by force of arms, he lobbied among the Croats and Serbs at the Military Frontier.

[9][10] The speech promoted the struggle for national liberation, asking for Croatian to become the official language in schools and offices, with its gradual introduction in the public life.

All his speeches in the parliament and at county assemblies staunchly advocated the freedom and independence of Croatia, so they could be published only in Branislav, an illegal Illyrian magazine printed in Belgrade.

Under his influence, the ban Josip Jelačić convened the Croatian Parliament on June 5, 1848, opposing the explicit imperial order.

After he became the prefect of Zagreb County in 1861, he was loyal to Vienna, implementing policies targeted against Croats and the South Slavs and hounding his former friends who remained faithful to their Illyrian ideals.

[15] Due to financial problems, Kukuljević was forced to sell his enormous library, numbering 12,000 volumes, which was acquired by the Croatian Academy of Arts and Sciences in Zagreb.

[16][17] One of manuscripts from his library is a tragedy, Skanderbeg, written on the basis of Andrija Kačić Miošić's work.