Little is known about the life of Harold R. Heaton, except that he was a newspaper cartoonist of some skill, an actor, and a failed playwright.

Called "a forgotten cartoonist" in a short article in the Chicago Daily Tribune on October 8, 1942, Heaton joined the Tribune staff an illustrator in about 1885, gradually rising to the position of front-page cartoonist, signing himself as "H.R.H." By 1892 his drawings were a popular feature of the Sunday edition and in 1893 he produced weekly commentaries on the World's Columbian Exposition. In 1897 Anderson's Art Galleries in Chicago mounted an exhibition of Heaton's work which included 190 Tribune illustrations and cartoons and 19 watercolors of his travels abroad.

Despite his success as an artist, in 1899 Heaton quit the Tribune and joined the theatrical company of William Gillette, appearing in productions of Sherlock Holmes and then several other dramas. In 1906 he wrote a play called Lady Jim, but apparently he wasn't very successful as a playwright or an actor for in 1908 he returned to his artistic career as a political and editorial cartoonist for the Tribune's arch competitor, the Inter-Ocean.

Now signing his pictures "Harold Heaton" and appearing daily on the front page beginning in mid-1908, at first Heaton' subject matter consisted mainly of state and national politics or commentaries on international topics. However, by the end of 1909 he had narrowed his scope to concentrate on lampooning Chicago Mayor Fred Busse and his cohorts and appointees, and State's Attorney John E. Wayman. By 1913, Heaton's cartoons were no longer featured on the Inter-Ocean's front page, but on inside pages he continued to express opinions on issues of the day, with such topics as prison reform, the activities of Teddy Roosevelt or unrest in Ireland.

When the Inter-Ocean folded in 1914, Heaton apparently returned to a theatrical life, for he acted on Broadway between 1920 and 1932, starting with The Guest of Honor and finishing with The Boy Friend in 1932. He died about 1940, although it is not known exactly when or where.