Chapman was born in London, England, in 1876. At the age of 17 he joined the Independent Labour Party and was later secretary of the London ILP Federation. Chapman was a linotype operator by trade as well as a union secretary. Upon leaving England he was made a life member of the ILP. He emigrated to New Zealand in 1905. He settled in Wellington and became secretary of both the Wellington Typographical Union and Wellington Journalists Union. During World War I he was an advocator for dependents of servicemen and their rehabilitation. He became a member of the National Reparation Board. He was keenly interested in the work of the Red Cross Movement and was President of the New Zealand Red Cross for 25 years. He was also a worker for the Wellington Free Ambulance as a representative of the Red Cross. He was also a member of the Wellington Technical Board of Governors.
He was a Wellington City Councillor from 1919–1925 and 1929–1941, and also served on the Wellington Hospital Board. Chapman served three separate terms on the Wellington Harbour Board from 1919–21, 1925–31 and 1933–41. In 1915, Chapman ran for Mayor of Wellington as the Social Democratic candidate. In a three horse race, he came a distant third. He ran for mayor a further three times as the Labour Party's nominee. He ran in 1925, 1927 and 1938 placing second on each occasion.
He contested the electorate in the and came third behind Robert Alexander Wright and William Henry Peter Barber. He contested the electorate in the for the Labour Party and came third behind Hugh Campbell and Gilbert McKay. In, he stood in the Hawke's Bay electorate again and came a distant third after Gilbert McKay and Andrew Hamilton Russell. In the, he stood in the electorate and was beaten by the incumbent, Robert Alexander Wright, who had also beaten him in 1908. In 1928, Chapman was elected as the Member of Parliament for Wellington North which he held until the seats abolition in 1946. He then became the Member for from 1946 until 1954 when he retired. In 1945 he was appointed a member of the Wellington Rehabilitation Committee.
Later life
In 1935, he was awarded the King George V Silver Jubilee Medal. Chapman died in Wellington in 1957, aged 80, survived by a step-son and step-daughter. He was buried at Karori Cemetery in Wellington.
