A number of his works are listed on the U.S. National Register of Historic Places for their architecture.
In 1902, as a skilled journeyman carpenter, he worked on the Willard Hotel, Owl's Club, and Desert Botanical laboratories in Tucson, Arizona.
In that same year, Jaastad was able to start his own contractor business where he would design small but remarkable residential buildings for private individuals.
He worked in neighborhoods within Armory Park, West University, and North Speedway.
In 1908, he completed extensive courses in architecture and he enrolled in the University of Arizona where he was a part of an electrical engineering program.