he was born in ballarat to waiter donald dewar and sarah dallas. he was educated in melbourne and became a rural worker, before mining at chiltern. his union involvement saw him move away to become a firewood cutter, and around 1903 he settled at mudgee. he later became a brewer, and in 1921 was appointed to the new south wales legislative council as a labor member. he served until the reconstitution of the council in 1934, and later retired to mount isa. he died in sydney in august 1953.