He started out at the Sports Argus in Birmingham, moving to London in 1912 to become the political cartoonist for the short-lived Labour Party mouthpiece, the Daily Citizen.
He specialised in cartoons of horseracing, cricket and golf, and stayed at the Mail for over twenty years, enjoying enormous popularity.
In his capacity as a sports cartoonist, he became friends and golf partner with Arsenal manager Herbert Chapman, and one account says it was a combination of clothing worn by Webster that inspired Chapman to add white sleeves to Arsenal's red shirts.
The same year, in New York City, Webster married Mae Flynn, a former member of the Ziegfeld Follies, and their wedding was covered by the newsreels.
In December 1935, he married Ida Michael, an American showgirl who had starred on Broadway and in the Dorchester Cabaret in London.