Kennedy was born in Bath, the son of John Kennedy and Amelia Maria Briggs. His father, who died in March 1845, had been the British Chargé d"affaires in Naples, Italy and the Secretary of Legation to the United States.A. His great-grandfather was Archibald Kennedy, 11th Earl of Cassilis.
Kennedy was educated at Harrow School from 1858 to 1863. He then went up to Trinity College, Cambridge from where he graduated with a Bachelor of Arts degree in 1868.
By profession, he was a police magistrate and Justice of the Peace. During his time at Cambridge, he also rowed at bow in the First Trinity VIII in the Head of the River Race in 1867 and ran the two and three miles races at the University Sports in 1867 and 1868. In the 1861 census, he was resident at Leamington Priors, Warwickshire and in 1871 he was resident at the George Hotel in Nottingham.
Their children included:
Gilbert Lyon Kennedy (1875–1945)
David Macomb Kennedy (1878–1899)
Humphfrey Hayes Kennedy (1882–1918), who was a lieutenant-colonel in the Seaforth Highlanders and killed in the First World War
John de Navarre Kennedy O.B.E. (1888–1979) who became a judge in Canada
During his time at Cambridge, Kennedy represented Trinity College at cricket with appearances against Huntingdonshire in May 1866 and June 1867.
He first played football for the Wanderers in December 1866, making his debut in a 1–0 defeat by Old Etonians. He played in the FA Cup match against Crystal Palace on 20 January 1872, which ended in a 0–0 draw, with both teams progressing to the semi-finals.
The Scottish XI was made up from players from London and the Home Counties with "Scottish connections". On leaving university, he became a barrister, being admitted as a pupil of the Inner Temple in January 1867 and called to the bar on 30 April 1870.
From 1883 to 1889, he was on the Midland Circuit and served as recorder at Grantham.
From 1889 to 1907, he was a Metropolitan Police magistrate, serving at Marlborough Street Police Court and later at Greenwich and Woolwich. He was also a Justice of the Peace in London, Essex, Hertfordshire, Middlesex, Kent and Surrey. His publications included A Guide to the Coal Mines Regulation Acting, 1887 and The Law of Land Drainage and Sewers.
At the time of the 1901 census, he was resident at Linden Gardens, Kensington, London, and described as a "Metropolitan policeman".
Following his retirement, he settled at "Saint David"s", Broadstairs in Kent. Kennedy died in Thanet, Kent, on 2 January 1909.
He was also a regular member of the Wanderers club and an occasional cricketer. In his final year he was a member of the school football XI. Over the next eight seasons, he was a regular member of the side, making a total of 41 appearances, scoring 8 goals. He also represented Middlesex against Surrey and Kent and for London against Sheffield in 1867 and was a member of the Football Association committee from 1869 to 1870.
