William Ogilvie Esq joined the Speyside Militia in 1794 as an Ensign. He moves to the 11th foot a year later, where he gets promoted to Lieutenant. He sees action in the Napoleon Wars, where he was taken prisoner by the France for approximately a year. After being released in a prisoner exchange, he moved to the 52nd regiment. He remained with the regiment until c1802. Between c1802 and c1812, William served as a Clerk in the War Office.

in 1797 William married Christian Patison, daughter of the Rev. John Patison of Bristo-Street Edinburgh. 

In 1812 he was served male heir to Alexander Ogilvie of Boyne, who died in 1604 by the sheriff of Banffshire. He then makes a claim to the House of Lords claiming the titles of Earl of Findlater, Lord Banff and Baron Banff. The claim is referred to the Committee of Privileges. He is then known as Earl of Findlater, Sir William Ogilvie of Carnousie or Sir William Ogilvie of Boyne.

George Canning sued Sir William in 1813 for not being able to help him secure the seat as MP for the Royal Burgh of Banff.

He died at Causewayside, Newington, Edinburgh in 1825 and is buried at East Preston Street Cemetery, Edinburgh, Midlothian, Scotland