Gytha Torkelsdotter was the daughter of Torkel Styrbjörnsson. Consequently she was the granddaughter of the disinherited Swedish prince Styrbjörn Starke, the conqueror of Jomsborg, and Tyra, the daughter of Harold Bluetooth king of Norway and Denmark. However, this descent from the old Swedish and Danish royal houses is believed to be a later invention to give her and her numerous sons some claim to royal blood. Gyda or Gytha was certainly the daughter of Torkel or Thorkil, but her father's connections to Scandinavian royalty should be considered not proven.

In 1019, she married the Anglo-Saxon nobleman Godwin of Wessex, apparently as his second wife (his first wife having been a Danish princess). They had several children together, of whom five sons became earls at one time or another, three remaining earls in 1066. Among their children were Harold II of England and Tostig Godwinson, who later faced each other at the Battle of Stamford Bridge; their eldest daughter was Edith of Wessex, Queen consort of Edward the Confessor.

After the Battle of Hastings, Gytha had pleaded unsuccessfully with the Conqueror for the return of the body of her slain son Harold II. Four of her sons were killed in two successive battles - Tostig at Stamford Bridge, and Harold II, Gyrth, and Leofwine at Hastings. Her surviving son (and youngest son) Wulnoth lived nearly all his life in (pleasant) captivity in Normandy until the Conqueror's death 1087. Only her eldest daughter Queen Edith (d. 1075) still held some power (however nominal) as widow of Edward the Confessor.

According to the Anglo-Saxon Chronicle, Gytha left the Kingdom of England after the Norman conquest of England, together with the wives or widows and families of other prominent Anglo-Saxons. Presumably, after all the Godwin family estates were confiscated by the Conqueror, there was little hope left. Little else is known of Gytha's life or future, although it is probable that she went to Scandinavia (like her granddaughter and namesake) where she had relatives.