21 Feb 1914 Special Reserve Commission Lieutenant on probation, from the Dublin University Contingent, Officers Training Corps.
28 July 1914 Start of the Great War.
4 Aug 1914 Britain declares war on Germany.
1 Oct 1915 Mobilised.
1915–1916 Served in Egypt.
1 Apr 1916 Captain RAMC.
1916–1917 Served in France.
1917–1918 Served in India.
1 June 1918 Permanent Regular Army Commission Lieutenant RAMC.
1918–1921 Served in East Persia.
1 Apr 1919 Captain RAMC.
Sept 1922 Married Edith Constance nee Roark.
1922–1924 Served with the British Army of the Rhine.
1924 Specialist in Pathology.
1924–1925 Served in Egypt.
1925–1929 Served in Malaya.
1925–1926 Deputy Assistant Director of Pathology.
Jan–Nov 1927 Served in Hong Kong.
1 Oct 1927 Major RAMC.
Malta 10 Mar 1931 Major and Mrs J H C Walker arrived on board the transport Lancashire.
Deputy Assistant Director of Pathology and Hygiene Malta (DADPH). While at Malta, he gained experience with Brucella melitensis infections, and contributed in the formation of a scheme for the pasteurisation of the milk supply.1
Malta 1932 DADPH Malta.
1933 Part of the winning team of the inter-service golf cup tournament.
Malta 8 June 1933 Home leave.
Malta 29 Sept 1933 Returned from leave.
Malta 1934 Deputy Assistant Director of Pathology and Hygiene (DADPH) Malta.
Malta 10 July 1935 Home leave.
Malta 3 Sept 1935 Returned from leave.
Malta 23 Apr 1936 Returned to England, tour expired. Posted to Porton.
1936–1940 Physiologist Defence Experimental Station Porton.
1940–1942 Chief Instructor Chemical Warfare School Porton.
13 Apr 1942 Lieutenant Colonel RAMC.
1942–1943 Commanding Officer No 102 General Hospital.
1943–1944 Assistant Director of Medical Services HQ 49 Division.
1944–1945 Served in North West Europe.
1945–1946 Served in India.
1945 Commanding Officer No 104 Indian General Hospital.
1945–1946 Assistant Director of Medical Services (ADMS) HQ 303 Bengal and Assam area.
9 Sept 1946 Colonel L/RAMC.
1946–1947 ADMS HQ Singapore District.
25 Sept 1947 Made an Officer of the Order of Leopold with Palm, Croix de Guerre 1940 with Palm.
1947–1948 ADMS HQ South Western District.
19 Sept 1948 Retired. Joined the Public Health Laboratory Service in September 1948, and was attached to the Cambridge laboratory. He carried out for the World Health Organisation a survey of the laboratory facilities in Indonesia, and prepared a report for the development of a comprehensive laboratory service.
1949 Director of the Public Health Laboratory Luton.
1955–1960 Director of the Public Health Laboratory Maidstone.
1962 Demonstrator in the Department of Pathology Cambridge. At Cambridge he became interested in the numerous isolations of Brucella abortus from herd milks, which led to the formation of a working party under his chairmanship, to investigate the value and the application of the milk ring test in detail.
30 Jan 1964 Died suddenly at his home in Cambridge aged 70 years.