In 1851, prior to the establishment of responsible government, Osborne was elected to the semi-elected Legislative Council. He represented the
electorate of East Camden until the granting of self-government in 1856. Subsequently, at the
first election under the new constitution he was elected to the Legislative Assembly as one of the two members for
the same seat. He was subsequently defeated at the
1858 election and then retired from public life. He did not hold a parliamentary or ministerial position. His brother
Alick was an elected member of the Legislative Council from 1851 to 1855. while his sons
Patrick, and
James, were also members of the Legislative Assembly. ==References==