Hill-Trevor was the third son of Arthur Hill, 3rd Marquess of Downshire, and his wife Lady Maria (née Windsor).
By arrangement parts of the estates, including Brynkinalt in Wales, passed to Lord Edwin, who assumed by Royal licence the additional surname of Trevor.
As Lord Edwin Hill-Trevor, Lord Trevor was a Captain in the North Shropshire Yeomanry Cavalry, promoted Major in 1862, but retired from the regiment prior to its amalgamation into the unified Shropshire Yeomanry regiment in 1872.
[1] Lord Trevor married, firstly, Mary Emily, daughter of Sir Richard Sutton, 2nd Baronet, in 1848.
Trevor died in December 1894, aged 75,[2] and was succeeded in the barony by his son from his first marriage, Arthur.