Born 1426 in Copenhagen. Parents: Didrik, Count of Oldenburg, and Helvig of Slesvig.
After Adolf of Slesvig in 1448 had rejected the Danish crown, it was offered to Kristian om September the same year. In return he married King Kristoffer's widow. He was crowned in Copenhagen 28 of October 1449, elected in southern Norway in June 1449, crowned in Trondheim Autumn 1449. Took over all of Norway from Karl Knutsson in May 1450. In 1457 he was asked to become King of Sweden and was crowned in Uppsala 3 of July 1457. In 1459 he became Duke of Slesvig and Count of Holstein. He was deposed in Sweden in 1464. He died in May 1481 in Copenhagen.
Married 26 of October 1459 to Queen Dowager Dorotea. Children: Hans, Margareta (1456-1487) Queen of Scotland, Fredrik I (1471-1533) King of Denmark and Norway.