John Miller Andrews was born in Comber, County Down, and educated at the Royal Belfast Academical Institute.
After leaving school he entered the textile business, becoming a director of the family linen bleaching company and also the Belfast Rope Works. He came from a very well known and influential family in County Down. His mother was a sister of Viscount Pirrie, the chairman of Harland and Wolff, and his younger brother Thomas, had been one of the designers of the Titanic and had perished when the ship sank on its maiden voyage in 1912.
In 1902 he married the daughter of a Bolton stockbroker, Jessie Ormrod, and they went on to have one son and two daughters.
His family were heavily involved in Unionist politics, and John was elected to the Northern Ireland Parliament in 1921, serving as MP for County Down, and then Mid-Down until 1953. Given his background in industry, he was a significant figure in the formation of the Ulster Unionist Labour Association after the Great War and went on to become Minister of Labour under Viscount Craigavon from 1920 to 1937. This was a hugely challenging position, given the decline of some traditional industries in the 1920s and the impact of the Great Depression in the early 1930s.
In 1937 he was appointed Minister of Finance, but the pinnacle of his political career came in 1940 when he became the second Prime Minister of Northern Ireland. His appointment came at the height of the Second World War and there was growing dissent with the Stormont Government, especially with the failure to prepare the city of Belfast for the impact of the Blitz in 1941. In 1943 a backbench rebellion forced him from office. He was replaced by Sir Basil Brooke.
Throughout his life he was an enthusiastic and active member of the Orange Institution, holding the positions of County Grand Master of Down, Grand Master of the Loyal Orange Institution and Imperial Grand Master.
He was a proud member of Comber White Flag LOL No. 244.