His parents were Anne Petronelle Tangen, and Morten Mortensen Ogarden, a former parliament member for the Liberal Party, both from Tynset Municipality.
He completed the examen artium at Aars og Voss` school in Christiania in 1875 and the cand.
Helge Groth wrote "Of all the Norwegian poets and authors, none more directly influenced Olav Aukrust than Ivar Mortensson-Egnund."
He lived at the Einabu farm with the poet’s retreat up along Norwegian Highway 29, near the Einunna river bridge, for much of his life.
He was arrested in 1881 when he led a rebellion in Skien in support of Johan Sverdrup,[4] parliamentary reform and Nynorsk.
Mortensson called the magazine a "communist-anarchist organ for the country" and published extensive material from the international anarchist movement.
The following year he held a 17 May independence celebration in Tynset Municipality, where he argued against cowardliness of the members of the Norwegian Constitutional Assembly, but praised the French Revolution.
Fedraheimen ceased publication in 1891, two years after Mortensson-Egnund resigned as editor; his successor was Rasmus Steinsvik.
In 1909 Mortensson-Egnund was diocese curate in Hamar, and he was ordained as a priest in Norway the following year.
In 1915, when Vidar was the first magazine for Anthroposophy published in Norway, it opened with an article by Mortensson-Egnund that drew relationships with the mythological Víðarr.