William Henry Giles Kingston was born in Harley Street, London, on 28 February 1814. He was the eldest son of Lucy Henry Kingston (d.1852) and his wife Frances Sophia Rooke (b.1789), daughter of Sir Giles Rooke, Judge of the Court of Common Pleas. Kingston's paternal grandfather, John Kingston (1736-1820), was a Member of Parliament who despite having a plantation in Demerara staunchly supported the Abolition of the Slave Trade. His father, Lucy, entered into the wine business in Oporto, and Kingston lived there for many years, making frequent voyages to England and contracting a lifelong affection for the sea.
He was educated at Trinity College, Cambridge, and afterwards entered his father's wine business but soon indulged in his natural bent for writing. His newspaper articles on Portugal were translated into Portuguese, and assisted the conclusion of the commercial treaty with Portugal in 1842, when he received from Donna Mariada Gloria an order of Portuguese knighthood and a pension.
His first book was The Circassian Chief, a story published in 1844, and while still living in Oporto, he wrote The Prime Minister, an historical novel, and Lusitanian Sketches, descriptions of travels in Portugal. Settling in England, he interested himself in the emigration movement, edited in 1844 The Colonist and The Colonial Magazine and East India Review, was honorary secretary of a colonisation society, wrote in 1848 Some Suggestions for a System of General Emigration, lectured on colonisation in 1849, published a manual for colonists, How to Emigrate, in 1850, and visited the western highlands on behalf of the emigration commissioners. He was afterwards a zealous volunteer and worked actively for the improvement of the condition of seamen. But from 1850 his chief occupation was writing books for boys, or editing boys' annuals and weekly periodicals.