 He met Louis I Kahn and for post-graduate architectural studies he entered Kahn's Master's Studio at the University of Pennsylvania, Philadelphia, where he graduated in 1959.After graduation Sauer worked in a number of Philadelphia architect's offices and then in 1961 he started his own office with William Winchel as Winchel and Sauer, Architects and in 1962 as Louis Sauer Associates.Frustrated that his market-developer focused Philadelphia practice isolated him from working with economically disadvantaged social groups, in 1968 he organized 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.