He was born in Ostroróg in the Poznań Province as a son of Stanisław, Podstoli (Deputy Pantler) of Kujawy and Governor of the Brzeg and Kujawy Districts, in a family of Greater Poland magnates who were willing to cooperate with the Czech Hussites and resented the rule of Lesser Poland nobles as well as the influence of the clergy. From 1453 to 1455, he studied in Erfurt, and then probably returned to the Kingdom of Poland and subsequently continued his studies in Bologna where he obtained a doctorate in canon and civil law as a layman in 1459; from 1458 to 1460 he taught canon law. Having permanently returned to the Kingdom of Poland around 1461, he worked first in the Royal Chancellery, and then became a diplomat. He took part in drawing up the terms of the Peace of Thorn after the Thirteen Years’ War with the Teutonic Order; he was also sent as an envoy to two popes: Paul II (1464) and Pius II (1466–1467); in the latter case, together with Bishop of Chełmno and Pomezania Wincenty Kiełbasa, he unsuccessfully tried to have the terms of the Peace Of Thorn approved and to have the excommunication of those subjects of the Teutonic Knights who went to the Polish side lifted. During his next legation (to Saxony in 1471), he was imprisoned for at least a year, perhaps at the instigation of Matthias Corvinus. From 1465, he held a number of public positions: from 1465 to 1472 he was Castellan of Międzyrzecze, from 1472 to 1474 he was probably Crown Treasurer, from 1474 to 1500 he was Castellan of Poznań, from 1493 to 1498 – General District Governor of Greater Poland, and in 1501 he became the Governor (Voivode) of the Poznań Province. Apart from his public activity after 1464, he only left two small written works. Probably the later one was his 1467 speech to Pope Pius II entitled Peroratio domini Ostroróg coram domino Apostolico, which included praise for the Poles’ military exploits, starting with the figure of Krak (Grakch) described in Kadłubek’s chronicles and the glorious missions undertaken by kings Władysław Jagiełło and Władysław Warneńczyk. He wrote his second work, which was much larger and probably earlier, between the mid-1460s and 1477 (the second date is usually given, but some even claim that it was written from 1447 to 1460). The work, which has been preserved in two versions, one of which is shorter and one is longer, was entitled “Memorandum on the system of the Republic” or “Memorandum on ordering the Republic” (Monumentum pro comitiis generalibus regni sub rege Casimiro pro Reipublicae ordinatione congestum or …pro suae Reipublicae utulitate congestum); this consisted of short articles on relations between the Church and the state and on matters of the state. Ostroróg died in his castle in Grodzisk in 1501.