Here I should note the use of the term Canuck for Johnny's last name, which might seem odd to those of us who don't live in Canada. Many outside Canada think the word is only used of French Canadians or that it is derogatory. This doesn't seem to be the case. The word Canuck was coined in the 18th or centuries, although its etymology is unclear. According to The Random House Dictionary it was an Americanism first recorded around 1835, specifically referring to French Canadians. While the term Canuck may have originally been used of French Canadians, however, since the 19th century it has been used of any Canadian. This explains why it would be used as Johnny's last name or, for that matter, the name of Vancouver's hockey team (the majority of British Columbia being English in descent, rather than French). As to the term being derogatory, that varies according to how it is used and who's using it. Among Canadians it is safe to say that the term is not offensive, but among other peoples from other nations it can be used in such a way that it is a derogatory term.
As to Johnny Canuck himself, he featured prominently in political cartoons for thirty years. It was towards the end of the 19th century that he gradually fell out of use. It is difficult to say why this happened, as the use of other national personifications would continue unabated until after World War II. It would take the superhero craze of the late Thirties and early Forties to revive the character.
In 1938 Action Comics featuring Superman was published by Detective Comics Inc. (one of the companies which would become DC Comics). The phenomenal success of Superman would create a demand for superheroes that would insure that comic books would be filled with them for the next ten years. The superhero craze did not simply affect comic books in the United States, but in Canada as well. And just as Will Eisner turned Uncle Sam into a superhero for Quality Comics, so too did Johnny Canuck become a superhero. It was in 1941 that the manager of Toronto based Bell Features threw down a challenge for cartoonist Leo Bachle (then only fourteen): he had to create an exciting feature for the company's comic book line.
To this end young Bachle took the old national personification Johnny Canuck and transformed him from a burly lumberjack into a young fighter pilot, complete with leather headgear, goggles, flight jacket, and high topped boots. A captain in the Royal Canadian Air Force, Johnny had no superpowers, but had excellent athletic ability and was a great aviator. Johnny Canuck debuted in Dime Comics #1, February 1942. The character proved a roaring success, perhaps the most successful Canadian superhero save for Nelvana of the Northern Lights. His adventures continued for 28 issues of Dime Comics, ending in 1946. In 1995 Canada Post issued stamps commemorating the superheroes of the past, including Seventies hero Captain Canuck, Eighties heroine Fleur de Lys, Golden Age heroine Nelvana of the Northern Lights, Superman, and, of course, Johnny Canuck. Johnny was portrayed as he was in the comic books, with his aviator's cap and flight jacket.
In 1965 Johnny Canuck would be revived again, this time by American mystery writer James Moffatt. Strictly speaking Moffatt's version of Johnny was not the personification of Canada, but merely a Canadian private eye (who is one quarter Sioux) who changed his name to Johnny Canuck out of patriotism. Moffatt's Johnny Canuck adventures appeared only in paperback and are more or less forgotten, which may be a good thing. Reportedly they were poorly written and about as Canadian as the movie Rose Marie with Nelson Eddy and Jeanette MacDonald.
It was in 1970 that the Vancouver received a National Hockey League expansion team named the Canucks. Signed to the Canucks in 2006, Roberto Luongo's face mask featured Johnny Canuck in his guise as a lumberjack. In the 2008-2009 Johnny Canuck was used as one of the shoulder logos for their jerseys, although again as a lumberjack (although one proposed shoulder logo portrayed him as the pilot of Bell Features' comic books). Sadly, the team's official mascot is Fin, an anthropomorphic killer whale (while I realise orcas are found frequently in the north Pacific, I must confess I don't particularly identify them with British Columbia myself...), rather than Johnny Canuck himself. Curiously, the mascot of junior ice hockey team the Vancouver Giants, Jack, resembles Johnny Canuck to a large degree.
Over the years Johnny would figure in a few songs. Composer Henry Herbert Godfrey wrote two of the more famous songs. In 1900 he wrote both "Johnny Canuck's the Lad" and "When Johnny Canuck Comes Home." The drama "The Yellow Bag" from 1907 featured a song simply entitled "Johnny Canuck." The character would also be the subject of a few plays. In 1978 there was a play entitled Hurray for Johnny Canuck, loosely based on the comic book hero. In January 2006 the play Johnny Canuck and the Last Burlesque debuted in Montreal, positing that after World War II Johnny became a burlesque star. More recently, a professional wrestler took the name of "Johnny Canuck," again portraying him as a lumberjack.
Although not as well known outside Canada as Uncle Sam or John Bull, Johnny Canuck has had a long history. Although appearing infrequently after World War II, the character still resurfaces from time to time in plays and other media. I have seen arguments that Johnny Canuck should be the official mascot of the Vancouver Canucks rather than Fin (with which I would agree) and even that he should have been the mascot of the 2010 Winter Olympics in Vancouver. And while his appearance has varied over the years (he has been a lumberjack, a farmer, a rancher, and an aviator), he has survived through it all. I have no doubt he will be around for quite some time to come.