MacArthur was born in Scranton, Pennsylvania, the sixth of seven children of stern evangelist William Telfer MacArthur and Georgiana Welsted MacArthur.[2] Early in life, MacArthur developed a passion for reading. Declining to follow his father into ministry, he moved to the Midwest and soon became a successful reporter in Chicago, working for the Chicago Tribune and Chicago Daily News. MacArthur joined the United States Army for World War I, and served in France as a private assigned to Battery F, 149th Field Artillery, a unit of the 42nd Division, The Rainbow Division.[3] He recounted his wartime experience in 1919's A Bug's-Eye View of the War.[4] After the war, he wrote several short stories, two of which, "Hang It All" (1921) and "Rope" (1923), were published in H. L. Mencken's The Smart Set magazine.[2] Eventually he settled in New York City, where he turned to playwriting.
His second marriage was to the stage and screen actress Helen Hayes, from 1928 until his death. They lived in Nyack, New York. He was preceded in death by his daughter, Mary, who died of polio in 1949 at the age of 19. The shock of her death hastened MacArthur's own, according to those who knew him. Their adopted son, James MacArthur, was also an actor, best known for playing Danny "Danno" Williams on the very popular American television series Hawaii Five-O.
The Front Page (1928), with Ben Hecht, made into the 1931, 1945, and 1974 motion pictures of the same name, the 1940 film His Girl Friday, and the 1988 movie Switching Channels
