Ragnar Frisch was born on 3 March 1895 in Christiania as the son of gold- and silversmith Anton Frisch and Ragna Fredrikke Frisch (née Kittilsen). The Frisch family had emigrated from Germany to Kongsberg in Norway in the 17th century and his ancestors had worked for the Kongsberg Silver Mines for generations; Ragnar's grandfather Antonius Frisch had become a goldsmith in Christiania in 1856. His family had thus worked with precious metals like silver and gold for at least 300 years.

Being expected to continue his family Business, Frisch became an apprentice in the David Andersen workshop in Oslo. However at his mother's advice, while doing his apprenticeship Frisch also started studying at the Royal Frederick University. His chosen topic was economics, as it seemed to be "the shortest and easiest study" available at the university, and passed his degree in 1919. In 1920 he also passed his handicraftsman tests and became a partner in his father's workshop.

Frisch married Marie Smedal in 1920 and they had a daughter, Ragna. His granddaughter, Nadia Hasnaoui (Ragna's child), became a Norwegian television performer. After his first wife died in 1952, he remarried in 1953 with childhood friend Astrid Johannessen. who died in 1980.

In 1921 Frisch received a fellowship from the university which enabled him to spend three years studying economics and mathematics in France and England. After his return to Norway, in 1923, although the family's Business was having difficulties, he continued his scientific activity, believing that research, not jewellery, was his real calling. He published a few papers about probability theory, started teaching at the University of Oslo during 1925 and, in 1926, he obtained the Dr. Philos. degree with a thesis in mathematical statistics.

Frisch was one of the founders of economics as a modern science. He made a number of significant advances in the field of economics and coined a number of new words including econometrics and macroeconomics. His 1926 paper on consumer theory helped set up Neo-Walrasian research. He formalized production theory (1965).

In econometrics he worked on time series (1927) and linear regression analysis (1934). With Frederick V. Waugh, he introduced the celebrated Frisch–Waugh theorem (Econometrica 1933) (sometimes referred to as the Frisch–Waugh–Lovell theorem). In oligopoly theory he developed the conjectural variation approach. Frisch also is credited with introducing the term "model" in its modern economic sense by Paul Samuelson, based on a 1930 Yale University lecture.

Although his fellowship was extended to travel to Italy and France, the next year Frisch had to return to Norway because of his father's death. He spent one year to modernize and recapitalize his family's workshop by selling family assets and to find a jeweller to manage the Business for him. Then he resumed academic work, in 1928 being appointed Associate Professor of statistics and economics at the Oslo University. During 1927 and 1928 Frisch published a series of articles on the statistics of time series. In 1929 he published his first important essay on econometric methodology, "Correlation and scatter in statistical variables", followed in the same year by "Statics and dynamics in economic theory", which introduced dynamics in economic analysis.

Frisch became a full Professor at the university in 1931. He also founded at the university the Rockefeller-funded Institute of Economics in 1932 and became its Director of Research.

His 1933 work on impulse-propagation Business cycles became one of the principles of modern New Classical Business cycle theory. He also helped introduce econometric modeling to government economic planning and accounting.

During the occupation of Norway by Nazi Germany Frisch was imprisoned in Bredtveit concentration camp from 17 October 1943, then in Berg concentration camp from 22 November 1943, then in Grini detention camp from 9 December 1943 to 8 October 1944.

There is a bibliography of Frisch's writings up to 1960 in

Ragnar Frisch received the Antonio Feltrinelli prize from the Accademia Nazionale dei Lincei in 1961 and the Nobel Memorial Prize in Economic Sciences in 1969 (awarded jointly with Jan Tinbergen) for "having developed and applied dynamic Models for the analysis of economic processes".