Francis Grant was the elder son of Archibald Grant of Ballintomb, Morayshire, a descendant of James Grant, 3rd Laird of Freuchie, by his wife Christian, daughter of Patrick Nairne of Cromdale, was born at Ballintomb in 1658. He was educated at King's College, Aberdeen, and afterwards at Leiden University where he was a favourite pupil of the learned civilian Johannes Voet. Soon after his return to Scotland Grant took a prominent part in the discussions on the constitutional questions arising out of the revolution. Some of the older lawyers insisted on the inability of the convention of estates to make any disposition of the crown. Grant strongly opposed this notion, and published a treatise arguing strongly for the power of the estates to establish a new succession. Grant was admitted an advocate on 29 January 1691, and, owing to the reputation which he had made by this treatise, quickly acquired a large practice. In the exercise of his profession and Grant was created a Baronet of Monymusk, Aberdeen in the baronetage of Nova Scotia with remainder to his heirs male by patent dated 7 December 1705. A few years later he was appointed a Lord Ordinary of the Court of Session in the place of James Murray, Lord Philiphaugh, and took his seat on the bench on 10 June 1709 as Lord Cullen, his title being derived from the name of his paternal estate in Banffshire, which had been ratified to him in 1698, but which he afterwards sold. In 1713 he purchased the estate of Monymusk in Aberdeenshire, which in 1890 was still the residence of his family, from Sir William Forbes of Pitsligo. On 17 May 1720 he obtained a grant of supporters and an addition to his coat-of-arms, at the same time taking as one of his mottoes the words Jehovah Jireh, the only instance in Scottish heraldry of a Hebrew motto. He died at Edinburgh on 23 March 1726, and was buried in Greyfriars churchyard on 26 March.
Character assessment
He was a deeply religious man, a learned lawyer, and a conscientious judge. Robert Wodrow records: Wodrow relates that Grant and a few other lawyers set up a "society for prayer, and a kind of correspondence for religiouse purposes about the 1698.… This meeting laid the first foundation of that noble designe of reformation of manners in King William's time and Queen Ann's time that did so much good".
Family
Grant married three times. On 15 March 1694, he married Jean, daughter of the Rev. William Meldrum of Meldrum, Aberdeenshire. With his first wife he had three sons and three daughters. His eldest son, Archibald, succeeded to the baronetcy, and represented Aberdeenshire from 1722 to May 1732, when he was expelled the house for the share which he had taken in the management of the charitable corporation. His second son was William Grant, Lord Prestongrange. On 18 October 1708, he married Sarah, daughter of the Rev. Alexander Fordyce of Ayton, Berwickshire. they had two daughters. His third wife was Agnes, daughter of Henry Hay and they married in 1718.