In 1902, he founded the Societat Catalana de Biologia and later on he became Professor of physiology at the University of Barcelona, where he promoted the study of physiology. In the Laboratorio Bacteriológico Municipal and in the Institut de Fisiologia he worked as a teacher and researcher.
Since 1916 until 1921 he was a member of Catalan parliament representing the Republican party. In 1920 he promoted the creation of the Escuela de Fisiología Catalana with the support of the Mancomunitat. In 1939 he moved to Venezuela where he was nominated teacher of the Universidad de Caracas and continued his research projects in different physiological fields. His works were recognised world-wide, obtaining the Kalinga prize from the UNESCO in 1955. He directed periodical publications: "Treballs de la Societat de Biologia", "Annals de l'Institut de Fisiologia" and some physiological studies.
- La vida anaerobia (1901)
- Tratado de fisiología (1902)
- La antitoxia renal (1907)
- La infecció (1911)
- La unidad funcional (1919)
- Los mecanismos de correlación fisiológica (1920)
- Los fundamentos de la biología (1943)
- Sistema neurovegetativo (1947, 1954)
- The Bridge of Life (1950)
- Classics of Biology (1955)
- La novel·la del besavi (1944, 1969)
- Sunyer metges, pare i fill (1944)
- Fisiología humana (1962)
- J. Carreras i Barnés "August Pi i Sunyer Semblança Biogràfica" I.E.C. 1998