Architect and urban planner. He worked in the styles of purism and emotional functionalism, focusing primarily on the design of public buildings, especially hospitals, schools, and churches.

After finishing his secondary-school studies in Prague (1914), he then enrolled at the Czech Technical University (1914–1915, 1917–1921). In 1921, he continued his studies at the Academy of Fine Arts in Prague (1921–1924) under Jan Kotěra and Josef Gočár. In his early years, he was particularly influenced by Kotěra’s work and modern Dutch architecture. Between 1920 and 1936, he undertook numerous study trips across Europe, visiting Italy, France, Switzerland, and Finland. While still a student, together with his academy classmate František Fiala (1895–1957), he participated in several architectural competitions. Their greatest success came in the competition for the art pavilion (House of Arts) in Moravská Ostrava (1923), where they won second place; their adapted purist design was realized over the following two years. Wallenfels also made his mark as an urban planner, producing several award-winning competition projects, such as the regulation plan for Malá Strana and a development plan for Kolín, where he also designed a Czechoslovak Church congregation building (1932). His designs for purist residential buildings were also implemented.

From 1928, he was employed as an architect at the provincial office, later at the Provincial National Committee, focusing primarily on the design of buildings for healthcare and social purposes. In Německý (Havlíčkův) Brod, he designed the extensive complex of the Provincial Institute for the Mentally Ill (1920–1934) and the hospital kitchen (1935). He also designed the Institute for the Blind in Prague-Krč (1930–1933) and Pírk’s Sanatorium in Mladá Boleslav (1933–1934). He worked at the Ministry of Health between 1948 and 1958. In addition to his design work, he published in leading Czech journals, including Stavitel and Architektura.

He was a member of the Club for Old Prague, the Association of Architects, and the Association of Academic Architects.