The Castle was completed in 1892 as the home of Charles and Kate Eisenbeis. His business interests were diverse including a bakery, brick works, lumber mill, brewery, bank and a hotel. In 1878, when Port Townsend became the first incorporated city in Jefferson County, its citizens elected Eisenbeis as the first mayor.

In 1925, a Seattle attorney bought the Castle as a vacation place for nuns teaching in Seattle schools. This plan did not work out well and in 1927 the Jesuit priests purchased the building for use as a training college. The priests spent their sixteenth and final year of training here studying ascetic theology.

The Jesuits left in 1968 and the building was converted into a hotel. The elements “Manresa” and “Castle” were taken from the two previous owners to create the current name.