'Harald Hardrada (the eponym is believed to mean "strict ruler") was the son of Sigurd Syr, a Norwegian petty-king ruling in the Buskerud region. Allegedly Sigurd was descended from King Harald Fairhair but modern studies do not endorse this genealogy.
He was born around 1015, and by the age of 15 was in the army of Olaf Haraldsson fighting to reclaim the Norwegian throne from the Danish Cnut. Olaf was defeated and Harald emigrated to the Rus lands around Kiev, the lands of Grand Prince Yaroslav. He became captain there, and by 1034 was in Constantinople (though he would have called it Miklagard) where he eventually came to command the Varangian Guard. He sent his wages back to Yaroslav, and in 1042 left Constantinople, returned to Rus, and gathered men. Perhaps he had heard that Cnut's grip had been loosened and that Olaf's illegitimate son Magnus (the Good) was sitting the Norse throne.
A summer of raiding the Danes (in 1046) persuaded Magnus that Harald had power, and he agreed to share the kingship in return for a share of Harald's raid-loot. Next year Magnus was dead, and Harald was sole king of Norway. From then until 1064, while ruling peacefully enough at home, Harald raided the Danish coast in support of a claim to that throne as well. In 1064 he relinquished this claim, and was immediately approached by Tostig, Earl of Northumbria to seek the throne of England (which had, after all, been Cnut's). On the death of Edward the Confessor, Harald and Tostig made their armed play for power, invading in Yorkshire.
The English pretender, Harold Godwinson (claiming the throne despite being having sworn to Edward that he would deliver it to William of Normandy), marched north and met Harald's forces at the battle of Stamford Bridge. Harald asked for the throne, Harold (note spelling) offered him six-and-a-bit feet of English soil, and in the event it was the latter offer which prevailed. Subsequently the battle has been treated as closing the Age of the Vikings, which may make Hardrada "the Last Viking".
(Interestingly, in light of the stories about Godwinson's death at Hastings, Harald's death is said to have been as the result of an arrow, but in the throat rather than the eye. Sadly there were no tapestries made of the abortive invasion.
Harald married a Keivan princess, Elisiv, around 1044, and by her had 2 daughters. She was his Queen in Norway but rumour persists that he (also) married a Norse girl, Tora, by whom he had two sons, Magnus and Olaf, each of whom ruled as king of Norway, sharing the throne from 1067 to 1069, when Magus died, and Olaf ruled alone.
And his body only stayed in English soil for a year, before being dug up and moved to a church in Trondheim.