He was the only son of Henry IV (II) the Faithful, Duke of Żagań, by his wife Matilda, daughter of Herman, Margrave of Brandenburg-Salzwedel.

The young Henry V gained his political experience at the side of his father, taking part in negotiations with his Jan of Ścinawa in 1341, who give Wschowa to them.

Immediately after he took control over the government, Henry V oriented his politics towards recovery lands that were lost during his late father's rule.

However, thanks to the losses among Konrad I's army, the Polish king was able to retain the last Greater Poland lands which had been in the hands of Henry III's descendants.

The events of 1344 involved Henry V in the Bohemian politics, and a year later, when war broke out between Silesia and Bohemia, the Duke of Żagań supported his sovereign with troops while he tried to recover Wschowa.

In 1356, together with Nicholas the Small, Duke of Ziębice, Henry V was involved in a diplomatic mission to Constantinople, where he took part in the pilgrimage to Palestine.

Shortly after, Henry V paid the sum of 600 fine silver to his only surviving uncle, Konrad I of Oleśnica, for his rights over that land.

His rule proved too harsh in that he had to face the fury of his own vassals, who even kidnapped him, but shortly afterwards released him in the basement of St. Jakob's Church in Głogów.