That would be Two Shillelagh O’Sullivan sung by Bing Crosby and written by Perry Botkin and Preston Foster. Botkin was a session musician who played with, well, everybody, from Al Jolson to Roy Rogers to Spike Jones, and then was Bing’s music director for many years.
Preston Foster, born in New Jersey, was an actor on Broadway and in Hollywood (he had roles in Annie Oakley and The Informer, among many others). He also was a singer and songwriter. In 1952, he and Botkin wrote about the fantastical O’Sullivan, “This bronco-busting Irishman from the sod of Erin’s Isle” who didn’t need a six gun, because he always had his two shillelaghs (“the Tipperary rifle, you never have to reload it”).
Inspired, no doubt, by the tall tales of Pecos Bill and Paul Bunyan, O’Sullivan could lick them both. In fact,
“He was so strong… He could put his right hand in his own left pocket, and hold himself out at arm’s length. ”
“No man could do that!”
“It’s O’Sullivan I’m talking about!”
“Oh, well he could.”
Listen to Bing sing about O’Sullivan here: