He was born in Drøbak as a son of historian Kristian Schreiner (1874–1957) and physician and anthropologist Alette Schreiner (1873–1951), and grew up in Kristiania. He was married briefly to his youth friend, later editor, Minister of Social Affairs, and member of Parliament Kirsten Hansteen, from 1928, and from 1930 he was married to Astri Høst. While he was a student he was a member of the radical political organization Mot Dag.
Schreiner finished his secondary education in 1921, and enrolled at the University of Oslo where he majored in history in 1927. In 1933 he defended his doctorate, over timber export and trade politics in the early 17th century (Nederland og Norge 1625–1650. Trelastutførsel og handelspolitikk). He lectured at the University of Oslo from 1939, and was appointed professor in 1946. Following the outbreak of World War II he was arrested first in February 1942, being incarcerated at Bredtveit concentration camp until March. He was later arrested in October 1943 along with other University faculty. He was incarcerated in Bredtveit concentration camp from October to November 1943, Berg concentration camp from November to December 1943 and Grini concentration camp from December 1943 to December 1944. In 1946 and 1947 he co-edited the two-volume book Griniboken along with August Lange, with contributions from several of the prisoner at Grini. He chaired the society Den norske historiske forening from 1947 to 1955, and edited the society's journal Historisk tidsskrift during the same period. He was main editor of the five volume Trondheim bys historie (1956–1973), and Vårt folks historie (1961–1964).
- Sogner, Sølvi. "Johan Schreiner". In Helle, Knut. Norsk biografisk leksikon (in Norwegian). Oslo: Kunnskapsforlaget. Retrieved 10 August 2009.
- Torgersen, Rolf Normann. "Per Schreiner". In Helle, Knut. Norsk biografisk leksikon (in Norwegian). Oslo: Kunnskapsforlaget. Retrieved 29 January 2010.
- Ottosen, Kristian, ed. (2004). Nordmenn i fangenskap 1940–1945 (in Norwegian) (2nd ed.). Oslo: Universitetsforlaget. p. 607. ISBN 82-15-00288-9.
- Giertsen, Børre R., ed. (1946). Norsk fangeleksikon. Grinifangene (in Norwegian). Oslo: Cappelen. p. 330.
- Henriksen, Petter, ed. (2007). "Johan Schreiner". Store norske leksikon (in Norwegian). Oslo: Kunnskapsforlaget. Retrieved 10 August 2009.
- Wasberg, Gunnar Christie (2007). "Den norske historiske forening". In Henriksen, Petter. Store norske leksikon (in Norwegian). Oslo: Kunnskapsforlaget. Retrieved 10 August 2009.
- "Historikk" (in Norwegian). Norwegian Historical Association. Retrieved 28 April 2011.