Mr. Jack is an American comic strip by Jimmy Swinnerton which ran in William Randolph Hearst newspapers from August 30, 1903 until 1935.

[1] Mr. Jack, a philandering playboy tiger, may be the first developed cartoon animal character, a type that has since become a staple in the comics medium.

[1] Jimmy Swinnerton began his career in 1892 as a young illustrator for the San Francisco Examiner, one of William Randolph Hearst's newspapers.

[1] At first fairly generic, over time individual characters began to emerge, the most popular being the womanizing playboy "Mr. Jack", who first appeared on May 17, 1903.

[3][4] Jack's rakish ways made him a target of protests that he was a bad example for children, and after 1904 his strip was moved to the sports section, seen as a more adult and male area of the paper.

On the whole, he is a popular figure among the less conservative characters in his universe: he is often seen as the jovial life of the party, charming to women and admired by men.