Thorolf Kveldulfsson (modern Icelandic: Þórólfur Kveld-Úlfsson) was the oldest son of Kveldulf Bjalfasson and brother of the Norwegian/Icelandic goði and skald Skalla-Grimr. His ancestor (great uncle) Hallbjorn was nicknamed "halftroll", possibly indicating Norwegian-Sami ancestry.
He served as a retainer of Harald I of Norway (Harald Fairhair). Thorolf is a hero of the early part of Egils saga.
Thorolf was the eldest son of Kveldulf and Salbjorg. Taking after his father in stature, he grew up tall and strong. His character, however, resembled that of his mother's side of the family, and he is described as being attractive, accomplished, friendly, energetic, and popular with everyone he meets. At age 20, he began raiding, taking out longboats during the summer with a band of men and his maternal uncles Olvir Hnufa (Hump) and Eyvind Lamb. He spent winters at home with his father, and summers conducting lucrative raids.
Upon conquering Fjordane, Harald demanded the service of all landowners in the province. Against his better judgement and despite a premonition that Harald would not bring good fortune to his family, Kvedulf sent Thorolf to join Olvir in the King's service. Olvir had dropped out of viking raiding, and had become the king's court poet. As a retainer of Harald, he fights on the latter's own ship at the Battle of Hafrsfjord. After Harald's conquest of Norway Thorolf becomes his governor (lendmann or lendr maðr) over the northern region of Norway and is responsible for collecting tribute from the Sami to the north (finneskatt ). In this capacity he took part in an expedition by King Faravid of Kvenland against the Karelians.