King Albert died of dysentery on 27 October 1439. His widow, Elisabeth—Emperor Sigismund's daughter—gave birth to a posthumus son, Ladislaus. The Estates of the realm offered the crown to Vladislaus, King of Poland, but Elizabeth had his infant son crowned king on 15 May 1440. However, Vladislaus accepted the Estates' offer and was also crowned king on 17 July. During the ensuing civil war between the two kings' partisans, Hunyadi supported Vladislaus. Hunyadi fought against the Ottomans in Wallachia, for which King Vladislaus granted him five domains in the vicinity of his family estates on 9 August 1440.

Hunyadi, together with Nicholas of Ilok, annihilated the troops of Vladislaus' opponents at Bátaszék at the very beginning of 1441.Their victory effectively put an end to the civil war. The grateful King appointed Hunyadi and his comrade joint Voivodes of Transylvania and Counts of the Székelys in February. In short, the King also nominated them Ispáns of Temes County and conferred upon them the command of Belgrade and all other castles along the Danube.