| Class 1Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2006, 2012, 2018, and 2024.The next election will be in 2030. | C | Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, and 2016, and 2022.The next election will be in 2028. |
| # | Senator | Party | Dates in office | Electoral history | T | T | Electoral history | Dates in office | Party | Senator | # |
| 1 | John C. Frémont | Democratic | Sep 9, 1850 –Mar 3, 1851 | Elected in 1849. | 1 | 31st | 1 | Elected in 1849. | Sep 9, 1850 –Mar 3, 1855 | Democratic | William M. Gwin | 1 |
| Vacant | Mar 4, 1851 –Jan 29, 1852 | Legislature failed to elect. | 2 | 32nd |
| 2 | John B. Weller | Democratic | Jan 30, 1852 –Mar 3, 1857 | Elected late in 1852.Lost re-election. |
| 33rd |
| 34th | 2 | Legislature failed to elect. | Mar 4, 1855 –Jan 13, 1857 | Vacant |
| Elected late in 1857. | Jan 14, 1857 –Mar 3, 1861 | Democratic | William M. Gwin |
| 3 | David C. Broderick | Democratic | Mar 4, 1857 –Sep 16, 1859 | Elected in 1857.Died. | 3 | 35th |
| 36th |
| Vacant | Sep 17, 1859 –Nov 2, 1859 | |
| 4 | Henry P. Haun | Democratic | Nov 3, 1859 –Mar 4, 1860 | Appointed to continue Broderick's term.Lost election to finish Broderick's term. |
| 5 | Milton Latham | Democratic | Mar 5, 1860 –Mar 3, 1863 | Elected in 1860 to finish Broderick's term.Retired. |
| 37th | 3 | Elected in 1861.Retired. | Mar 4, 1861 –Mar 3, 1867 | Democratic | James A. McDougall | 2 |
| 6 | John Conness | Union | Mar 4, 1863 –Mar 3, 1869 | Elected in 1863. | 4 | 38th |
| 39th |
| 40th | 4 | Elected in 1865. | Mar 4, 1867 –Mar 3, 1873 | National Union | Cornelius Cole | 3 |
| 7 | Eugene Casserly | Democratic | Mar 4, 1869 –Nov 29, 1873 | Elected in 1867.Resigned. | 5 | 41st |
| 42nd |
| 43rd | 5 | Elected in 1871.Retired. | Mar 4, 1873 –Mar 3, 1879 | Republican | Aaron A. Sargent | 4 |
| Vacant | Nov 30, 1873 –Dec 22, 1873 | |
| 8 | John S. Hager | Democratic | Dec 23, 1873 –Mar 3, 1875 | Elected in 1873 to finish Casserly's term.Retired. |
| 9 | Newton Booth | Anti-Monopoly | Mar 4, 1875 –Mar 3, 1881 | Elected early in 1873.Retired. | 6 | 44th |
| 45th |
| 46th | 6 | Elected in 1877.Retired. | Mar 4, 1879 –Mar 3, 1885 | Democratic | James T. Farley | 5 |
| 10 | John Franklin Miller | Republican | Mar 4, 1881 –Mar 8, 1886 | Elected in 1881.Died. | 7 | 47th |
| 48th |
| 49th | 7 | Elected in 1885. | Mar 4, 1885 –Jun 21, 1893 | Republican | Leland Stanford | 6 |
| Vacant | Mar 9, 1886 –Mar 22, 1886 | |
| 11 | George Hearst | Democratic | Mar 23, 1886 –Aug 3, 1886 | Appointed to continue Miller's term.Successor elected. |
| 12 | Abram Williams | Republican | Aug 4, 1886 –Mar 3, 1887 | Elected in 1886 to finish Miller's term.Retired. |
| 13 | George Hearst | Democratic | Mar 4, 1887 –Feb 28, 1891 | Elected in 1887.Died. | 8 | 50th |
| 51st |
| Vacant | Mar 1, 1891 –Mar 18, 1891 | |
| 52nd | 8 | Re-elected in 1891.Died. |
| 14 | Charles N. Felton | Republican | Mar 19, 1891 –Mar 3, 1893 | Elected in 1891 to finish Hearst's term.Retired. |
| 15 | Stephen M. White | Democratic | Mar 4, 1893 –Mar 3, 1899 | Elected in 1893.Retired. | 9 | 53rd |
| | Jun 22, 1893 –Jul 25, 1893 | Vacant |
| Appointed to continue Stanford's term.Elected in 1895 to finish Stanford's term. | Jul 26, 1893 –Mar 3, 1915 | Republican | George C. Perkins | 7 |
| 54th |
| 55th | 9 | Re-elected in 1897. |
| Vacant | Mar 4, 1899 –Feb 6, 1900 | | 10 | 56th |
| 16 | Thomas R. Bard | Republican | Feb 7, 1900 –Mar 3, 1905 | Elected late in 1900.Lost re-election. |
| 57th |
| 58th | 10 | Re-elected in 1903. |
| 17 | Frank P. Flint | Republican | Mar 4, 1905 –Mar 3, 1911 | Elected in 1905.Retired. | 11 | 59th |
| 60th |
| 61st | 11 | Re-elected in 1909.Retired. |
| 18 | John D. Works | Republican | Mar 4, 1911 –Mar 3, 1917 | Elected in 1911.Retired. | 12 | 62nd |
| 63rd |