A New York author and journalist, he is most famous for his 1947 novel, Blood Brother, which was made into the 1950 film, Broken Arrow. His other works include Forests of the Night (1971) and White Falcon (1955).
He started his journalism career with the New York World-Telegram. He published his first novel, Two Loves, in 1934.
His 1949 biography of Sigmund Romberg was the inspiration for the musical film, Deep in My Heart (1954).
He was born in Brooklyn, New York. He died in his home city at the age of sixty-seven.
Actor John Travolta starred in Broken Arrow, a contemporary remake of the original film based on Arnold's novel, Blood Brother.