Cust was born in Hill Street, Berkeley Square, Middlesex, London in 1794. He was the sixth son of the 1st Baron Brownlow, and Frances Bankes. His older brothers were John Cust, 1st Earl Brownlow, Peregrine Cust, Rev. Henry Cockayne Cust and William Cust.
Cust was educated at Eton College, and the Royal Military College. In 1810, he joined the 16th Regiment of Light Dragoons as a cadet and was Captain of the 5th Regiment of Dragoon Guards from 1816 and Major of the 55th Regiment of Foot from 1821.
From 1818, Cust sat in Parliament as MP for Grantham until 1826 and then for Lostwithiel from 1826-32. In 1831, he was knighted and appointed a KCH by William IV for his military service, and in 1835 he was appointed as one of the Royal Commissioners for reporting on the plans offered by competitors for rebuilding the Houses of Parliament. In February, 1834 he was elected a Fellow of the Royal Society.
Aide to prince Leopold of Saxe-Coburg, widow of the Crown Princess Charlotte, he followed him to Belgium when he became the first king of the Belgians in 1831. Leopold made him a grand’officer in his order of Leopold in 1855.
In 1845, Queen Victoria appointed him Assistant Master of the Ceremonies and was promoted as Master of the Ceremonies in 1847. He joined the Canterbury Association on 27 May 1848, but resigned again on 22 November of that year. In 1849, the Cust River in Canterbury was named after Sir Edward Cust. The township of Cust was in turn named after the river.
In 1859 Cust was given the colonelcy for life of the 16th (The Queen's) Regiment of (Light) Dragoons (Lancers). In 1876, he was made a baronet.
Sir Edward wrote:
- Lives of the warriors of the thirty years' war, Warriors of the 17th century, part I, London: J. Murray, 1865
- Lives of the warriors of the thirty years' war, Warriors of the 17th century, part II, London: J. Murray, 1865
- Lives of the warriors who have commanded fleets and armies before the enemy, Warriors of the 17th century, 3 part III, London: J. Murray, 1869
- Mosley, Charles, ed. (2003). Burke's Peerage, Baronetage & Knighthood (107 ed.). Burke's Peerage & Gentry. p. 544. ISBN 0-9711966-2-1.
- Bain, Rev. Michael (2007). The Canterbury Association (1848-1852): A Study of Its Members’ Connections (PDF). Christchurch: Project Canterbury. pp. 27–28. Retrieved 22 September 2012.
- "Library and Archive Catalogue". Royal Society. Retrieved 26 December 2010.
- Reed, A. W. (2010). Peter Dowling (ed.). Place Names of New Zealand. Rosedale, North Shore: Raupo. p. 94. ISBN 9780143204107.
- Mills, T.F. "16th The Queen's Lancers". regiments.org. Archived from the original on 16 October 2007. Retrieved 3 October 2007.
- "No. 24299". The London Gazette. 25 February 1876. p. 884.
|Parliament of the United Kingdom|
Sir William Welby, Bt
| Member of Parliament for Grantham
With: Sir William Welby, Bt 1818–1820
James Hughes 1820
Sir Montague Cholmeley, 1st Bt 1820–1826
Sir Alexander Grant, Bt
| Member of Parliament for Lostwithiel
With: Viscount Valletort 1826–1830
Hon. William Vesey-FitzGerald 1830
Viscount Valletort 1830–1832
| Assistant Master of the Ceremonies
Sir Robert Chester
| Master of the Ceremonies
Sir Francis Seymour
Sir Joseph Thackwell
| Colonel of the 16th Lancers
Sir Charles Shute
|Baronetage of the United Kingdom|
|New creation|| Baronet
(of Leasowe Castle)