I remember my late father (in Northern Ireland) singing the words of this song (I can remember the verses about Growing whiskers on his chin and climbing up a tree and barking his shin. This would probably have been in the late 1950s (I was born in 1953) or possibly early 1960s, but as my father was born in 1916 and I see from above that the song was published in the 1920s and 1930s in Britain/USA (though it may date back to before the 1st World War), and hence it may have been popular when he was growing up. The name Michael Finnegan is certainly of Irish orgin as is John Brophy, who co-wrote (with Eric Partridge) the 1930 book on songs of the 1st World War.

A pity that there are now so few people left alive from the 1st World War, who might oteherwise be able to throw some light on this subject.