Bishop grew up in an Irish Catholic family and dropped out of school after the eighth grade. His father, a railroad man and later a policeman, found him various jobs, none of which he kept more than three weeks. He learned typing, shorthand, and bookkeeping at a secretarial school. In 1929, in his early 20s, his dad got him a job as a copyboy at the New York Daily News.
At the Daily News, he met Mark Hellinger, who would become film critic for the New York Daily Mirror, and later, a Hollywood movie producer. Bishop worked as Hellinger's assistant and later became a reporter at the Daily Mirror. In 1943, Bishop went to work for Collier's magazine as the war editor. He later worked for book publishers in New York. In 1947, Bishop was to go to Hollywood to work as a writer for Mark Hellinger but days before Bishop planned to resign and move to California, Hellinger died. In 1951, Bishop founded Gold Medal Books, a division of Fawcett Publications. Later he worked for Catholic Digest.
Bishop began collecting information about Lincoln's assassination in 1930, while he was still a cub reporter. His interest in Lincoln began with a remark from a nun in grade school about something Lincoln had said. Bishop's book brought him instant acclaim. The book was chosen as a Book of the Month Club offering and became a best seller.
On the basis of the book about Lincoln, Bishop became well known by readers throughout the country. For 26 years, he wrote a syndicated column, Jim Bishop: Reporter, that was distributed to hundreds of newspapers by Hearst's King Features Syndicate.
Among Bishop's other books are The Glass Crutch, the Biographical Novel of William Wynne Wister (1945), The Mark Hellinger Story, a Biography of Broadway and Hollywood (1952), The Girl in Poison Cottage (1953), Parish Priest (1953), The Making of a Priest (1954), Fighting Father Duffy (1956), The Golden Ham, a Candid Biography of Jackie Gleason (1956), Go With God (1958), The Murder Trial of Judge Peel (1962) [a famous Florida murder trial], A Day in the Life of President Johnson (1967), The Days of Martin Luther King, Jr. (1971), The Birth of the United States (1976).
Bishop's last book was his brutally honest autobiography, A Bishop's Confession (1981). Bishop died in 1987 in Delray Beach, Florida. He was 79.