He was born in Garčin in teacher's family. Year 1896. became a full member of Academy, and was an honorary doctor of Prague University, and an external member of the Czech Academy of Sciences. Historiographic work of monumental history of the Croats, Povijest Hrvata, near Kuglija published in five books (the 1899th to 1911th), it is not, unfortunately, managed to finish. Assessing the work of his, the other major Croatian historian, Ferdo Sisic (1914). Said: The production, scientific method and prolixity Klaić's work surpasses all previous works of its kind in our historiography while Jaroslav Sidak says that despite all its flaws, Klaićevo work remains in view XV. and XVI century by the abundance of their data, unrivaled to this day.