| Office: | President of the Storting |
| Term Start: | 1 January 1910 |
| Term End: | 31 December 1912 |
| Alongside: | Wollert Konow and Jens Bratlie |
| Primeminister: | Gunnar Knudsen Wollert Konow Jens Bratlie |
| Predecessor: | Edvard Liljedahl Gunnar Knudsen Carl Berner |
| Successor: | Jørgen Løvland Søren Tobias Årstad Gunnar Knudsen |
| Office1: | Minister of Finance |
| Term Start1: | 23 October 1907 |
| Term End1: | 19 March 1908 |
| Primeminister1: | Jørgen Løvland |
| Predecessor1: | Abraham Berge |
| Successor1: | Gunnar Knudsen |
| Office2: | Member of the Norwegian Parliament |
| Term Start2: | 1 January 1910 |
| Term End2: | 31 December 1912 |
| Constituency2: | Bakklandet |
| Term Start3: | 1 January 1907 |
| Term End3: | 31 December 1909 |
| Constituency3: | Bakklandet |
| Term Start4: | 1 January 1898 |
| Term End4: | 31 December 1900 |
| Constituency4: | Trondhjem and Levanger |
| Birth Name: | Johan Magnus Halvorsen |
| Birth Date: | 10 June 1853 |
| Birth Place: | Ålesund, Møre og Romsdal, United Kingdoms of Sweden and Norway |
| Death Place: | Trondheim, Sør-Trøndelag, Norway |
| Party: | Free-minded Liberal Party |
Johan Magnus Halvorsen (10 June 1853 - 14 February 1922) was a Norwegian politician for the Free-minded Liberal Party.[1] [2]
Halvorsen was born at Ålesund in Møre og Romsdal, Norway. He was a merchant by profession. He started his business career as a sales representative at Vanylven in Sunnmøre. In 1874 he became a director at Selje forbruksforening in Nordfjord. He later worked as a representative for several factories and businesses in Bergen. In 1881, he established himself as a merchant in Trondheim with a fish wholesaler. [3]
Halvorsen was a member of the city council of Trondheim 1895-1904 and again from 1910. He represented the city in the Norwegian Parliament 1898-1900 and 1903–12. He was Minister of Finance from 1907 to 1908 in cabinet of Prime Minister Jørgen Løvland. [4] [5]