Percy Whitlock studied at London's Royal College of Music with Charles Villiers Stanford and Ralph Vaughan Williams. From 1921-1930, Whitlock was assistant organist at Rochester Cathedral in Kent. He served as Director of Music at St Stephen's Church, Bournemouth for the next five years, combining this from 1932 with the role of that town's borough organist, in which capacity he regularly played at the local Pavilion Theatre. After 1935 he worked for the Pavilion Theatre full-time. A tireless railway enthusiast, he wrote at length and with skill about his interest. Sometimes, for both prose and music, he used the pseudonym "Kenneth Lark." He worked closely with the Bournemouth Municipal Orchestra; the orchestra's conductor from 1935-1940 was Richard Austin, whose father Frederic Austin dedicated his Organ Sonata to Whitlock.
Whitlock was diagnosed with tuberculosis in 1928. Near the end of his life, he lost his sight altogether, and he died in Bournemouth a few weeks before his 43rd birthday. For decades afterwards he remained largely forgotten. This neglect has eased in recent times, in particular through the activities and publications of the Percy Whitlock Trust, founded in 1983. The Percy Whitlock Trust was wound up in 2017, due to the expiry of copyright on Whitlock's compositions, and its assets and archive transferred to the Royal College of Organists.
- Six Hymn Preludes (1923, revised 1944)
- Five Short Pieces (1929)
- Two Fantasie Chorals (1931, revised 1933)
- Four Extemporisations (1932–33)
- Seven Sketches on Verses from the Psalms (1934)
- Sonata in C minor (1935–36)
- Plymouth Suite (1937)
- Reflections: Three Quiet Pieces (1942–45)
- Carillon (1932)
- March: Dignity and Impudence (1932–33)
- Concert-Overture: The Feast of St. Benedict (1934)
- To Phoebe (1936)
- Symphony in G minor for organ and orchestra (1936–37)
- Poem (1937)
- Wessex Suite (1937)
- Balloon Ballet (1938)
- Holiday Suite (1938–39)
- Ballet of the Wood Creatures (1939)
- Prelude, Air and Fugue (1939)
- Peter's Tune (1939)
- Fanfare on the tune "Song of Agincourt" (1940)
- Caprice (1941)
- O Gladsome Light (1917–18)
- Motet: The Saint whose praise today we sing (1923)
- Magnificat and Nunc Dimittis in G (1924)
- Jesu, grant me this, I pray (1924–28, revised 1945)
- Glorious In Heaven (1925)
- Communion Service in G (1927)
- Sing praise to God who reigns above (1928)
- Three Introits (1929)
- Magnificat and Nunc Dimittis in D (1930)
- Evening Cantata: Round me falls the night (1930)
- Magnificat and Nunc Dimittis (Plainsong, with alternate verses in Harmony) (1930)
- A Simple Communion Service (1930)
- Solemn Te Deum (1931)
- He is risen - Anthem for Eastertide (1932)
- Come, let us join our cheerful songs (1945)
- Percy Whitlock: Organ Sonata in C minor, Fantasie Choral No. 1, Five Short Pieces. John Scott/Organ of St. Paul's Cathedral, London. London: Hyperion Records, 2004. 1 CD.
- Percy Whitlock: Organ Sonata in C minor, Five Short Pieces, Reflections, March 'Rustic Cavalry'. Robert Gower/Organ of Selby Abbey: ASV, 1996. 1 CD
- Percy Whitlock: Holiday Suite, Music for Orchestra, Wessex Suite, The Feast of St. Benedict. Malcolm Riley (Organ), Gavin Sutherland/RTE Concert Orchestra. Hong Kong: Naxos, 2001. 1 CD.
- Percy Whitlock: Symphony in G minor for Organ and Orchestra (1936–37). Francis Jackson: Concerto for Organ, Strings, Timpani and Celeste Op. 64. Francis Jackson, Organist (Whitlock Symphony: York Minster; Jackson Concerto: Lyons Concert Hall, University of York). Jonathan Wainwright/University of York Orchestra. North Yorkshire: Amphion, 2000. 1 CD.
- The complete organ works of Percy Whitlock, Vol. 1. Graham Barber/Organ of Hull City Hall. Bedfordshire: Priory Records, 1996. 1 CD.
- The complete organ works of Percy Whitlock, Vol. 2. Graham Barber/Organ of Hereford Cathedral. Bedfordshire: Priory Records, 1997. 1 CD.
- The complete organ works of Percy Whitlock, Vol. 3. Graham Barber/Compton Organ of Downside Abbey. Bedfordshire: Priory Records, 1998. 1 CD.
- The choral music of Percy Whitlock. Choir of Rochester Cathedral, Roger Sayer (Director of Music), William Whitehead (Assistant Organist). Bedfordshire: Priory Records, 1996. 1 CD.
- Riley, Malcolm (2007): The Percy Whitlock Companion. Kent: The Percy Whitlock Trust.
- Riley, Malcolm (2003): Percy Whitlock: organist and composer (2d ed.). York: Ebor Press.
- Riley, Malcolm (23 September 2004). "Whitlock, Percy William". Oxford Dictionary of National Biography (online ed.). Oxford University Press. doi:10.1093/ref:odnb/55920. Retrieved 17 February 2019. (Subscription or UK public library membership required.)
- Whitlock, Percy. The South Eastern and Chatham Railway and the London, Chatham and Dover Railway Amalgamated. 1899 LOCOMOTIVES: Their Description, History, distinctive features and interest. Preface Archived 2008-08-07 at the Wayback Machine Retrieved 11-07-2009.
- Article in RCO Journal (Subscription required)