Matthias was second son of John Hunyadi, a successful general of the Kingdom of Hungary, who had risen through the ranks of the nobility to become regent of Hungary. After the death of Matthias's father due to plague outbreak in 1453, there was a two-year struggle between Hungary's various barons and its Habsburg king, Ladislaus the Posthumous, with treachery from all sides. Matthias was inveigled to Buda by the enemies of his house, and, on the pretext of being concerned in a purely imaginary conspiracy against Ladislaus, was condemned to decapitation, but was spared on account of his youth.

Later Matthias took advantage of the memory left by his father's deed - on 20 January 1458, Matthias was elected king by the Parliament. On the 24th of January 1458, 40,000 Hungarian noblemen, assembled on the ice of the frozen Danube, unanimously elected Matthias Hunyadi King of Hungary. Thus, on the 14th of February the new king made his state entry into Buda.

Under the rule of Matthias Hungary reached its greatest territorial extent of the epoch (present-day southeastern Germany to the west, Dalmatia to the south, Eastern Carpathians to the east, and southwestern Poland to the north). In the course of his expansion, Matthias strengthened his state's diplomacy. Apart from his regular network of relations with his neighbours, as well as the Pope and Kingdom of Naples, he established regular contacts with France, Burgundy, Switzerland, Florence, most German states, Russia and, occasionally, with Persia and Egypt.

Matthias' reign is considered one of the most glorious chapters of Hungarian history. Songs and tales refer to him as Matthias the Just, a ruler of justice and great wisdom, and he is arguably the most popular hero of Hungarian folklore. There is a Hungarian proverb still used today saying Matthias has died, justice is gone (Meghalt Mátyás, oda az igazság).