He was the eldest son of William Gronow of Court Herbert, Neath, Glamorganshire, who died in 1830, by Anne, only daughter of Rees Howell of Gwrrhyd.
Here he became one of the dandies of the town, and was among the very few officers who were admitted at Almack's, where he remembered the first introduction of quadrilles and waltzes in place of the old reels and country dances.
Sir Thomas Picton then took him out to Flanders as an honorary aide-de-camp but finding no employment for him, he was advised to join the 3rd battalion of his regiment[1] and was subsequently present at Quatre Bras and Waterloo.
[3] His victory was the result of extensive bribery, and a parliamentary investigation in June–July 1833 recommended that the corruption was so "open, general, and systematic" that the constituency should be completely disenfranchised.
[4] The bill did not pass the House of Lords, however,[5] with the effect that Gronow remained a member of Parliament until it was dissolved in December 1834.
According to the Morning Post, he left his widow and infant children "wholly unprovided for" at his death, aged 70 in Paris on 22 November 1865.