Sharman is the eldest son of Colonel William Sharman, for many years a member of the Parliament of Ireland for Lisburn, who dies in 1803 leaving him large estates. In 1805 he marries a wealthy heiress, Mabel Fridiswid Crawford, whose surname and arms he adds to his own.
Sharman Crawford supports Catholic Emancipation and the rights of tenants. He is also a member of the landed gentry. He is High Sheriff of Down for 1811. He is a member of the Parliament of the United Kingdom for Dundalk in 1835–37 and for Rochdale in 1841–52. He greatly increases the prosperity of the tenants on his large estates by extending and confirming the Ulster custom of tenant-right. The main objective of his long parliamentary career is to give legal effect to this right and extend it to other parts of Ireland.
In 1848 with James MacKnight, editor of the liberal Londonderry Standard, Sharman Crawford forms the Ulster Tenant Right Association which is supported by a group of radical Presbyterian ministers. He also supports MacKnight in forming, with Charles Gavan Duffy, editor of the Young Ireland newspaper The Nation, the all-Ireland Tenant Right League.
Sharman Crawford is the father of James Sharman Crawford, member of the Parliament of the United Kingdom for Down, (1874-78), Arthur Sharman Crawford, unsuccessful candidate for Down in 1884 and John Sharman Crawford, unsuccessful candidate for Down in 1880. His daughter is Mabel Sharman Crawford, adventurer, feminist and writer.
Sharman Crawford dies unexpectedly and peacefully at Crawfordsburn, County Down on October 17, 1861. He is buried in the family vault at Kilmore, County Down, where there is a monumental inscription. A great stone obelisk is erected in his memory on a hill at Rademon Estate, near Crossgar, County Down.