US Army Corps of Engineers. Sauer labelled himself conscientious objector, willing to carry out everything asked except to harm or kill, a deed which would get him in trouble. Nonetheless, he was able to complete his service and receive an honourable discharge. While travelling in Italy on furlough, he met the Italian architect Gino Valle at his home in Udine, where Valle introduced Sauer to the ideas and work of the American architect Louis I Kahn, who practiced in Philadelphia. Sauer returned to the United States in 1955, where he obtained his first architectural employment under Jules Gregory in Lambertville NJ. He then joined the 1956 summer session of Congrès International d'Architecture Moderne (CIAM) in Venice at the Istituto Universitario di Architettura spending a formative period studying under architects such as Giuseppe Samonà, Jacob Bakema and Giancarlo De Carlo. Sauer remained another six months in Venice before returning to America to work for the Philadelphia Planning Department under Edmund Bacon on the Society Hill Redevelopment Plan. He met Louis I Kahn and entered Kahn's Master's Studio for post-graduate architectural studies at the University of Pennsylvania, Philadelphia, graduating in 1959. After graduation, Sauer would work in a number of Philadelphia architect's offices. In 1961, Sauer and collaborator William Winchel would open their first office Winchel and Sauer, Architects, renaming it to Louis Sauer Associates the following year. Frustrated that his market-developer focused Philadelphia practice isolated him from working with economically disadvantaged social groups, he organized in 1968 a separate architectural and planning office with David Marshall and Steven Kerpen – Peoples Housing, Inc – in Topanga, California that focused on design and construction for economically and physically disadvantaged social groups. Sauer also taught part-time throughout this period, architecture and urban design at Philadelphia's Drexel Institute of Technology (1960–65) and the University of Pennsylvania (1965–79). His decision to close his Philadelphia office in 1979 took many fellow practitioners by surprise, giving up a successful private practice and moving on to a full-time academic career as Head of Architecture at Carnegie Mellon University. Sauer felt strongly about the role of education for shaping future practitioners, believing that unless architectural schools learned to teach students how to design for increased building performance and to deal with society on realistic economic terms, society would simply deal architects out of the game. Between 1989, and 1997 Sauer returned to professional design practice in Montreal, Quebec, Canada,