So far as we can tell, it was written by Joseph B Geoghegan, a Lancashire music hall performer, in c.1866; though not, apparently, to the tune used nowadays. Immediately pirated by the broadside press, it achieved some currency in Ireland; where, within a few short years, it was confidently being claimed that it was an old song written there long ago. See thread  Johnny I hardly knew ya [sic].

The fact that we know (with reasonable, though not absolute, certainty) who wrote it doesn't mean that it oughtn't to be described as traditional now; but the original author ought to be credited at the same time. Geoghegan died in 1889.