Jack Callahan was born John Thomas Callahan in Brooklyn, New York. He was affiliated with the New York World newspaper from the early 1910s and involved in the creation of the crossword in 1913. He moved on to create a series of newspapers strips and panels, including 'Life's Little Ifs' (1915-1916), 'When You Were a Boy' (1916-1917), 'Big Moments in Little Lives' (1916), 'Bonehead Bill' (1916), 'Flivvers' (1916-1917), 'Over Here' (1918), and ; Cinderella Suze' (1918).
'Over Here' later appeared under titles like 'Hon and Dearie' and 'The Piffle Family' in papers like the Syracuse Evening Telegram and the New York Evening Journal throughout the first part of the 1920s. Among Callahan's other 1920s and 1930s creations are 'Freddie the Sheik' (1924-1928), 'Clarabelle's Cousin' (1928-1930), 'Dizzie's Eating House' (1930) and 'Home, Sweet Home' (1935-1940).
He found employment in the comic book industry in the second half of the 1940s. He worked on 'Tillie the Toiler' stories for Dell Publishing's Four Color line and had features in DC's More Fun Comics ('Curly's Cafe') and All Funny Comics ('Sunshine Nelly', 'Kafloppos'). He passed away from a heart attack while playing tennis in 1954.