Streatfeild was born in Clapham, where his father was a bank clerk. His grandfather was the vicar of East Ham, Essex. He studied at art college. A successful artist, he had a studio off the Kings Road in London. It has been suggested he received training under Henry Scott Tuke. He painted portraits of industrialists, the occasional actress and young children. He was acquainted with London society and was a friend of Robbie Ross, patron of the arts and a former lover of Oscar Wilde.
In 1914, Streatfeild became a mentor to the then-14-year-old actor and later famed author Noël Coward. Coward's social ascendancy began thanks to Streatfeild who, before his death, asked wealthy socialite Mrs Astley Cooper to take Coward under her wing. Mrs Astley Cooper continued to encourage her late friend's protégé, who remained a frequent guest at her estate, Hambleton Hall.
- Hoare, p. 32, confirms that this is the correct spelling, noting that Coward misspelled it in his memoirs.
- Hoare, Philip. "Something mad about the boy", The Independent, 11 April 1998, accessed 7 January 2014
- Day, p. 33
- Hoare, pp. 33–34
- Evangeline Julia Marshall, an eccentric society hostess (1854–1944), married Clement Paston Astley Cooper, grandson of Sir Astley Paston Cooper. She inherited Hambleton Hall in 1899, and there she entertained rising talents in the artistic world, including Streatfeild, the conductor Malcolm Sargent and the writer Charles Scott Moncrieff, as well as the young Coward. See Callow, Simon. "Englishman abroad", The Guardian, 19 April 2006, accessed 8 February 2009; "Evangeline Julia Marshall", The Peerage, accessed 8 February 2009; and "History", Hambleton Hall website, accessed 8 February 2009
- Hoare, pp. 39–43