Bullock was the son of iron merchant Frank M. Bullock, of Milhanger, Thursley, Surrey He was educated at Trinity College, Cambridge. Bullock normally went by his middle name of Malcolm rather than his first name. He reached the rank of Captain in the Scots Guards. In 1923 he was elected as the Member of Parliament (MP) for Waterloo in Lancashire, a position he retained until the constituency was abolished in 1950. He was re-elected in the new Crosby constituency at both the 1950 and 1951 general elections, before resigning as an MP in October 1953. In February 1954 he was created a baronet, of Crosby in the County Palatine of Lancaster.
Bullock married Lady Victoria Alice Louise Primrose, daughter of Edward Stanley, 17th Earl of Derby and widow of Neil Primrose, in 1919. They had one daughter, Priscilla, who married the racehorse trainer Peter Hastings, later Peter Hastings-Bass. Lady Victoria died in a riding accident in November 1927, aged 35. Bullock died in June 1966, aged 76, when the baronetcy became extinct. His great-granddaughter is Clare Balding.
- GRO Register of Births: Sep 1889 Bullock, Harold Malcolm, Dartford 2a 455
- Debrett's Peerage, Baronetage, Knightage and Companionage, 1963, pg 140
- Kelly's Handbook to the Titled, Landed and Official Classes, 1921, pg 291
- "Bullock, Captain Sir (Harold) Malcolm, (10 July 1890–20 June 1966), Hon. Colonel of 336 Medium Regiment, Royal Artillery." WHO'S WHO & WHO WAS WHO. 8 Jun. 2019
- "UK General Election results February 1950". Political Science Resources. Richard Kimber. Retrieved 24 August 2008.
- "UK General Election results October 1951". Political Science Resources. Richard Kimber. Retrieved 24 August 2008.
- "No. 40097". The London Gazette. 9 February 1954. p. 865.
- thepeerage.com Sir Harold Malcolm Bullock, 1st and last Bt.
- Bloch, Michael (28 May 2015). Closet Queens: Some 20th Century British Politicians. Little, Brown Book Group. ISBN 9781405517010.
- Bloch, Michael (16 May 2015). "Double lives – a history of sex and secrecy at Westminster". The Guardian. ISSN 0261-3077. Retrieved 22 July 2017.
- Hansard 1803–2005: contributions in Parliament by Sir Malcolm Bullock, Bt
|Parliament of the United Kingdom|
| Member of Parliament for Waterloo
|New constituency|| Member of Parliament for Crosby
|Baronetage of the United Kingdom|
|New creation|| Baronet