Wanting to move on to bigger things, Theisen had a high-rise in mind and had one constructed. As it was being constructed, residents told him it was too risky and began to call it Theisen's Folly. However, he proceeded on with it and the building was completed in around the time he achieved his citizenship. The building was designed by the Atlanta architectural firm of Morgan & Dillon, and constructed by Pensacola contractors Wills & Broughton. This Folly became a huge success after it housed a retail store and professional offices. To help its success were the facts that it was Pensacola's tallest building and had modern elevators.
During this time as well, he was threatened with losing all his assets if he kept the venture going. To fight back to those that issued such threats, Theisen had the Danish flag flown over the building until his death on April 1, 1934. He is buried in St. Michael's Cemetery.
The building was in use until the 1970s. From that point on until 1992, it fell into disrepair and was vacant. In 1992, businessman Ray Russenberger purchased and renovated the building to provide offices for his paging company Network USA. He restored the exterior to its original 1901 design.