Clergyman, who became Chaplain to the US Senate. Born in humble circumstances in Coatbridge (North Lanarkshire), Marshall lost his father at the age of four. He was educated at the local technical school and spent time in the British Navy. Finding himself called to the Ministry and aware his qualifications were unlikely to allow him to study in Scotland, Marshall emigrated for the USA, arriving at Ellis Island (New York) in 1927. He worked for a time in New Jersey before moving to Alabama, where he was given the necessary funding to attend a seminary in Georgia, graduating in 1931. After proving a popular pastor in the South, he moved to the New York Avenue Presbyterian Church in Washington DC in 1937 where he found himself in great demand. Despite a heart attack in 1946, Marshall was appointed Senate Chaplain in the following year. Following his premature death, Marshall's life was chronicled by his wife in the moving book A Man Called Peter (1951). This gave rise to a film of the same title starring Richard Todd in 1955. Remembered as an inspirational preacher, his published sermons still prove popular.
His son, also Peter, runs an evangelical ministry and speaks across the USA.