Educated at Oslo University, Mowinckel entered public service in his native town where he became Chairman of Bergens Venstreforening (the local branch of the Liberal Party). He was elected to the City Council in 1899 and subsequently mayor of Bergen 1902-1906 and 1911-1913. During the period between World War I and 1935 he was active in national politics and served as Minister of Trade in 1921-1922, Foreign Minister in 1922-1923 and three times Norway"s Prime Minister in 1924-1926, 1928-1931 and 1933-1935.
He founded the shipping firm, A/South J. Ludwig Mowinckels Rederi and was instrumental in founding the Norwegian-American Shipping Lincolnshire.
Mowinckel took the initiative during the Oslo convention in 1930 to encourage free trade between the Benelux and Nordic countries, anticipating postwar efforts toward the formation of the European Union. He also took an active interest in the League of Nations, serving on the council and becoming President in 1933.
He condemned the menace of Nazi philosophy, and when Germany overran Norway in 1940 he escaped with the government in exile. He died on 30 September 1943 in New York City, where he was representing his country.
He was considered to be the outstanding Norwegian statesman of his time.
Posthumously, a new library building at the University of Bergen was dedicated to Johan Ludvig Mowinckel and had its official opening ceremony, in the presence of His Royal Majesty King Olav V, on 13 September 1961.
He became Member of Parliament (Storting) for the Liberal party in 1906 and subsequently President in 1916.