Lord Castlerosse was appointed High Sheriff of Kerry for 1851.
The following year he was returned to parliament as one of two representatives for Kerry.
In 1856 he was appointed Comptroller of the Household under Lord Palmerston, a post he held until the government fell in 1858.

He was sworn of the Privy Council in February 1857.
When Palmerston resumed office in 1859, Castlerosse became Vice-Chamberlain of the Household, which he remained until 1866, the last year under the premiership of Lord Russell.
He again became Vice-Chamberlain of the Household in 1868 in William Gladstone's first administration.

In December 1871 he succeeded his father in the earldom and took his seat in the House of Lords.
He consequently resigned as Vice-Chamberlain (a post normally held by a commoner) and in February 1872 he was appointed a Lord-in-waiting, i. e. a government whip in the House of Lords.
In June of that year he was made a Knight of the Order of St Patrick.
The Liberal government fell in 1874.
Gladstone returned as prime minister in 1880, when Lord Kenmare was appointed Lord Chamberlain of the Household.

He held this office until 1885 and again briefly in Gladstone's third administration between February and July 1886.
Apart from his political career he was also Lord-Lieutenant of Kerry between 1866 and 1905.
Lord Castlerosse was appointed High Sheriff of Kerry for 1851. The following year he was returned to parliament as one of two representatives for Kerry. In 1856 he was appointed Comptroller of the Household under Lord Palmerston, a post he held until the government fell in 1858.
He was sworn of the Privy Council in February 1857. When Palmerston resumed office in 1859, Castlerosse became Vice-Chamberlain of the Household, which he remained until 1866, the last year under the premiership of Lord Russell. He again became Vice-Chamberlain of the Household in 1868 in William Gladstone's first administration.
In December 1871 he succeeded his father in the earldom and took his seat in the House of Lords. He consequently resigned as Vice-Chamberlain (a post normally held by a commoner) and in February 1872 he was appointed a Lord-in-waiting, i. e. a government whip in the House of Lords. In June of that year he was made a Knight of the Order of St Patrick. The Liberal government fell in 1874. Gladstone returned as prime minister in 1880, when Lord Kenmare was appointed Lord Chamberlain of the Household.
He held this office until 1885 and again briefly in Gladstone's third administration between February and July 1886. Apart from his political career he was also Lord-Lieutenant of Kerry between 1866 and 1905.
Valentine Browne, 4th Earl of Kenmare