Bjarni was mainly responsible for Iceland joining NATO in 1949, against significant opposition, and for giving the United States Air Force a lease on Keflavík Airport near Reykjavík, which was of major strategic importance during the Cold War.

[1] Bjarni was caricatured by the Nobel prize winning writer Halldór Laxness in his 1948 play Atómstöðin (The Atom Station).

[1] In 1956, when the left-wing parties formed a coalition government, Bjarni, out of office, became editor of Morgunblaðið, a leading conservative newspaper.

When Bjarni became prime minister, he received a congratulatory letter from the president of the United States, John F. Kennedy, only six days before his assassination.

[3] Bjarni served in this position until his death, which was caused by a fire at a government summer house at Þingvellir on 10 July 1970.