He was a granduncle of Frank and Albert Henrik Mohn,[2] and his niece Hanna married physician and politician Nils Yngvar Ustvedt.

[2] In 1861, when long-time professor Christopher Hansteen retired from an active academic career,[4] Mohn became the new manager of the city astronomical observatory.

His first article in the field, Stormene i Christiania fra 1837 til 1863 was published in 1863 in the journal Polyteknisk Tidsskrift, which he had edited from 1859 to 1862.

[1] His main work was Études sur les mouvements de l'atmosphère, written between 1876 and 1880 together with mathematician Cato Maximilian Guldberg.

[2] In 1874 Henrik Mohn was elected as senior honorary member of the Royal Meteorological Society of London.

A Festschrift was planned together with the fiftieth anniversary of the Meteorological Institute, but cancelled due to Mohn's death in September 1916 in Kristiania.

[2] The Mona Islands in the Kara Sea were named after Henrik Mohn by Fridtjof Nansen, who published the first detailed maps of the Russian Arctic.