Walter Prideaux was born 15 April 1806, at Bearscombe near Kingsbridge and Loddiswell, one of the six sons[3] of Walter Prideaux (d. 1832) of Kingsbridge and Plymouth, a partner in the Devon and Cornwall Bank, a Quaker associated with the Plymouth Brethren, having in 1812 sold Bearscombe[citation needed] and moved to Plymouth.

[4] It is not clear what relation he was to the ancient gentry family of Prideaux seated variously at Orcheton, Modbury; Adeston, Holbeton; Thuborough, Sutcombe; Soldon, Holsworthy; Netherton, Farway; Ashburton; Nutwell, Woodbury; Ford Abbey, Thorncombe all in Devon, and at Prideaux Place, Padstow, and Prideaux manor, Luxulyan, in Cornwall.

The wife of Walter Prideaux (Senior) was Sarah-Ball Hingston, a daughter of his partner Joseph Hingston (1764-1835) (Senior), merchant,[5] of Dodbrooke (adjacent to Kingsbridge) in Devon, by his first wife Sarah Ball (d.1790), a daughter of Joseph Ball of Bridgwater in Somerset.

[6][7] Prideaux is shown in a painting where discussions are taking place for a journey in a balloon by Charles Green, Thomas Monck Mason and Robert Hollond.

Prideaux was included in the painting with the artist, John Hollins, and William Milbourne James.