Although the later saga literature narrates stereotypical accounts about the two kings, Eystein is known to have improved the infrastructure and raised buildings and churches, particularly across the coast in Western Norway and Trøndelag, from Bergen to the fishing centre of Lofoten in the north.

Eystein's activities were especially centered in Bergen, which became an important international trade hub for fish at the time, helped by his construction projects.

His stories includes a so-called mannjevning (literally "comparison of men") between Eystein and Sigurd, in which the two boast about their skills and deeds in an attempt to outdo each other.

[2] In a similar fashion, Snorri also tells a story about how Eystein managed to cure the melancholy of a friend, by agreeing to regularly clear time to talk with him about what troubled him.

"[5] More reliable information, particularly about Eystein's building-projects, is offered in earlier sagas such as the work of Theodoric the Monk, a Norwegian chronicler who wrote in the late 12th century.

In practice, only Eystein and Sigurd ever ruled as kings, as Olaf was considerably younger and died when he was only seventeen years old, and virtually nothing is known about him beyond his name.

)[15] The existence of a now lost port in Agdenes dated to around Eystein's reign has been supported by recent archaeological surveys in the area.

[16] Eystein also improved the shelters in the mountain passes, notably at Hjerkinn in Dovre, to more comfortable houses with permanent supervision.

According to Snorri, it was "generally said that so many mourners never stood over any man's grave in Norway as over King Eystein's," at least since the death of Magnus the Good.

They had a daughter, Maria, who became the mother of the future royal pretender Olaf Ugjæva by her marriage to the lendmann Gudbrand Skavhoggsson.

Olaf was named king in 1165, during the Norwegian civil war era, but was subsequently defeated by Magnus Erlingsson and forced to flee the country.

"[5] The view of Eystein as a peaceful and domestically active king has been supported by modern historians such as Claus Krag, although noting that the literary embellishments should be disregarded.

[2] A stylized marble bust of Eystein, dated to before the middle of the 12th century,[2] was found during excavations at Munkeliv Abbey in 1853, and it represents the oldest known preserved portrait of a Norwegian king.

[2] To commemorate his status as founder of the fishing village of Kabelvåg (although it had been an important centre for at least a century), a huge statue of Eystein (Øysteinstatuen) by Arthur Gustavson was raised at Breidablikk in Vågan Municipality in 1935,[23] after an idea of architect Harald Sund.