A farmer's son, Strang grew up in Perthshire and attended the independent Morrison's Academy in Crieff.

After gaining a BSc in Genetics from the University of Edinburgh in 1964, he gained a Diploma in Agricultural Science from Churchill College, Cambridge and a PhD in Agricultural Science from Edinburgh, presenting the thesis "The genetic aspects of litter productivity in British pigs".

Strang was a minister under Harold Wilson and James Callaghan, serving as Parliamentary Under Secretary of State at the Department of Energy in 1974 and then at the Ministry of Agriculture, Fisheries and Food until 1979.

Strang was a member of the Tribune Group of MPs and the Campaign for Labour Party Democracy.

[5][6] He was Chairman of the All-Party Group for World Government[7] and served on the Environment, Food and Rural Affairs Committee.