Born in Pershore, Worcestershire, Leader was the eldest son of Benjamin Williams LEADER RA (1831-1923) of Burrows Hall, Gomshall, Surrey, and his wife, the Plymouth-born flower artist Mary Eastlake (1853-1938). He attended Charterhouse school and was admitted as a pensioner at Trinity, Cambridge on June 30, 1896. He studied art at Bushey and at Newlyn. Iris Green identifies him as a pupil of Stanhope FORBES and as attending the FORBES SCHOOL, but no date is specified.The records show that he sold his first painting, Surrey Pines, at NAG in 1904.

He was married to Isabella Anderson of Rosemerrin, Bude, Cornwall, and locally, in Lamorna, Leader lived at Oakhill (1911-13), The Reens (1913-14) and then built the house called Rosemerryn in the style of a Cornish manor in 1914-15.

He loaned his cottage at Oakhill to Laura KNIGHT and Harold KNIGHT temporarily when he and Belle moved on to their new home at Rosemerryn, but sadly he had little time to enjoy his creation. He was a Captain in The Queen's Royal West Surrey Regiment and Duke of Wellington's West Riding Regiment. Leader was killed in action on Oct 12, 1916 on active service in France at the age of thirty-nine.

Ella Louise NAPER designed his memorial plaque that hangs today in St Buryan Church (see Branfield, Ill, p46). He is also commemorated at Thiepval Memorial, Somme, France.
His wife, Isabella LEADER (Belle), also painted but seldom exhibited.