While in high school, Olesen started working for the construction company that his grandfather founded.  Following graduation, he joined the Navy and was in Officers’ Training as World War II came to an end.  He became a partner in the Jens Olesen Construction Company after the war, eventually rising to the position of president of the company. 

In 1962, Olesen became President of the Master Builders of Iowa.  At the time, he was the youngest person to attain that position.  He retired from Jens Olesen Construction in the 1980s, but remained very active in community affairs. 

He currently serves on the Board of Directors of the Grout Museum and has been in charge of the 11.5 million dollar capital fundraising campaign for the new Veterans addition.  The expansion is scheduled to open in 2008.