His parents were Pétur Havstein (17 February 1812 – 24 June 1875) Governor of North and East Iceland and Kristjana Gunnarsdóttir Havstein (20 September 1836 – 24 February 1927) sister of Iceland's first bank chairman, Tryggvi Gunnarsson.

[1] He was proposed the first Minister for Iceland on 31 January 1904 from 1 February 1904, and he served as such until 31 March 1909.

In 1931 a statue of Hannes by sculptor Einar Jónsson was unveiled in Reykjavik.

[1] The roundels on his and his wife's graves (see photo to left) were also by Einar Jónsson.

As a poet, Hannes Hafstein mostly wrote in the national romantic tradition, often with a humorous, even satirical, touch.