Peter Keler was enrolled at the Fachhochschule für Angewandte Malerei (college of applied painting) in Kiel from 1914 to 1916 and at the Kunstgewerbeschule (school of applied arts) in the same city from 1919 to 1921. He studied at the Staatliches Bauhaus in Weimar between 1921 and 1925. In 1921, he attended the preliminary course taught by Johannes Itten. From the winter semester of 1921/22 to 1925, he attended the wall painting department under Oskar Schlemmer and Wassily Kandinsky. During his time at the Bauhaus in Weimar, Keler devised colour designs for buildings and rooms such the office floor at the Fagus-Werk in Alfeld an der Leine and Walter Gropius’s director’s office in the Bauhaus Building. The furniture he designed during this period includes a Cradle which he completed for the first Bauhaus Exhibition of 1923. In the summer of 1922, Keler became a member of KURI (an acronym for constructive, utilitarian, rational, international), a group with constructivist ambitions active at the Bauhaus. From 1924 to 1925, he was employed as a staff journeyman. Fully trained, his task was to mediate between the master of form and the master of works.
After leaving the Bauhaus in Weimar, he opened his own studio for free and applied painting, advertising graphics and interior design that same year. From 1928 to 1936, he worked as a creative consultant for companies in the textile and machine industry in Saxony. From 1937 to 1945, the NSDAP banned him for exhibiting his work. During this period, he worked as a freelance architect in Berlin, as a set designer for the Tobis film company and curated an archive for war artists. After the end of the war, he accepted the invitation of the newly founded Hochschule für Baukunst und Bildende Kunst (school of architecture and visual art) in Weimar. Two years later, he was appointed professor, a position that he held until 1963. From 1965, he worked as a freelance architect in Weimar.