Blease, the son of William John Blease and Sarah Watts, was educated at McClure Public Elementary School and Belfast Technical College, the National Council of Labour Colleges and then the Workers' Educational Association.
Blease worked first as a shop apprentice from 1929, becoming a grocer's assistant and grocery branch manager between 1938 and 1940.
He stood unsuccessfully for the Parliament of Northern Ireland in Belfast Oldpark at the 1953 general election, and in 1965 his son William Victor Blease (usually known as Victor) was unsuccessful in Belfast St Anne's.
On 21 June 1978, he was created a life peer with the title Baron Blease, of Cromac in the City of Belfast.
In 1985, Blease worked with Paddy Devlin to found the Labour Party of Northern Ireland and he remained a trustee of the group until its dissolution in 1990.