He served as Comptroller of the Household under Lord Melbourne in 1841 and under Lord John Russell between 1846 and 1847 and as Treasurer of the Household under Russell between 1847 and 1852. The following year he assumed by Royal licence the surname of Sandys in lieu of Hill. Lord Sandys married Louisa, daughter of Joseph Blake, in 1837.
Lady Sandys died in April 1886.
He was Godfather to Arthur Cheek, who was was given the names "Arthur Marcus Hill" in his honour.
11th United Kingdom Parliament. 13th United Kingdom Parliament. 14th United Kingdom Parliament.
15th United Kingdom Parliament]
Sandys was Member of Parliament for Newry from 1832 to 1835 and for Evesham from 1838 to 1852.