Born in Sweden, the lantern-jawed Olaf was one of that country's leading circus acrobats. Although Sweden was neutral during the war, Olaf could not just casually watch as Europe fell before the Nazi menace. Thus, he left behind Sweden's peace and became a Blackhawk.
When the team adopted "secret identities" in the late '60s, Olaf at first had trouble coming up with anything until he was provided a suit of super-rubber by a Swedish scientist, Professor Neilson, which allowed him to become the Leaper. 
In the '70s when the majority of the team was based in the Cunningham Aircraft company, Olaf worked in Europe as a ski instructor. He had one of the new VTOL aircraft hidden in a mountain cave which he could use to join the team on short notice.  What Olaf did after Blackhawk disbanded the team is not known.
- Counted as the strongest of the Blackhawks
- This version of Olaf Bjornson (Earth-One), including all history and corresponding appearances, was initially erased from existence following the collapse of the original Multiverse in the 1985–86 Crisis on Infinite Earths limited series. However the ending of Convergence retroactively prevented that collapse, saving all the alternate realities, though in an "evolved" form. Even though versions of the character may have since appeared, this information does not apply to those versions.
- 153 Appearances of Olaf Bjornson (Earth-One)
- 3 Images featuring Olaf Bjornson (Earth-One)
- 1 Quotations by or about Olaf Bjornson (Earth-One)
- Character Gallery: Olaf Bjornson (Earth-One)