Subsequent political repression led him to emigrate to the U.S. in 1851 while the rest of the family temporarily stayed in Breslau, where Paul studied at the colleges of St. Elizabeth and Holy Spirit.

Their winning design proposal was partly based on notes Pelz had taken on prominent public libraries when he traveled to Europe to collect the prize in Vienna.

Pelz had the main role in the design of the building and the execution of its exterior, while Smithmeyer was instrumental in securing the commission and Casey supervised most of the interior finishings.

[3] In 1898, at the request of socialite Mary Foote Henderson, he proposed designs for a new Executive Mansion to replace the White House on what is now Meridian Hill Park.

His designs included Romanesque Revival (Carnegie Library of Allegheny, McGill Building, Memorial Bridge project), Gothic Revival (Antietam Cemetery gatehouse, Hot Springs Hospital, Grace Reformed Church), a hodgepodge of Neo-Medieval styles at Georgetown University's Healy Hall, French Renaissance (Miller House), Neo-Georgian (Elkins Mansion), American Federal (University of Virginia), Stick Style (several lighthouses, US Soldiers' Home Library), and Beaux-Arts (Library of Congress, Foraker Mansion, Meridian Hill Executive Mansion project).