William Binfield Wemyss was born in India on 15 Feb 1810. He was the son of Hon James Wemyss of Wemyss, in the Bengal Civil Service. His mother was Caroline Charlotte Binfield. His grandfather was the 5th Earl of Wemyss. He was a cadet in 1825 and posted to the 9th BLC in November 1826. William was promoted to lieutenant on 3 Dec 1828, acting Adjutant on 5 Dec 1829, and permanent Adjutant on 11 Dec 1830 until 10 June 1833. He was promoted to captain on 10 Oct 1836 and went on active service in Sind in 1843. He was with the regiment at Meenee and Hyderabad. He was appointed Brigade Major at Meerut from 16 may 1845 to October 1850, then Superintendent of the Remount Depot at Karnal from Oct 1850 to 1851.
Wemyss was promoted to Major on 2 Oct 1851 and Lieutenant-Colonel on 28 Nov 1854. He was officially appointed Commanding Officer of the 9th BLC in April 1855 although he had been in command since 1852. He exchanged to the 10th BLC on 2 Jan 1857. However he was on furlough from 30 Dec 1856 until 12 Dec 1859. His Indian Mutiny service with the 4th Bengal European Light Cavalry is dated from May 1858, then transferred to the 1st BELC on 28 Dec 1859, with the rank of brevet Colonel, until 1864. He was promoted to Major-General on 3 July 1867 and went on furlough from 10 Dec 1867 until his retirement. He was promoted to Lieutenant-General on 6 Feb 1875 and General on 1 Oct 1877. He was on the Retired List on 15 Feb 1880. He died at Highfield House, Guildford on 24 May 1890. He was married to Martha Rose Diana Smith, eldest daughter of Lieut-General Samual Smith who had commanded the 9th BLC in 1828. They were married at Nimach on 24 March 1832. They had eight children; 3 sons and 5 daughters. At least one of the sons died in infancy. Martha died on 23 Oct 1876 aged 63.
