Dennis Morgan took his pleasing tenor voice and in My Wild Irish Rose created the image of Irish entertainer Chauncey Olcott for generations to come. I doubt there are too many people who actually saw Chauncey Olcott perform in one of those tearful plays about the Auld Sod and they're not revived too often.
But Olcott as performer and credited songwriter endures, no St. Patrick's Day would be complete without some of Olcott identified songs like When Irish Eyes Are Smiling, Mother Machree, and A Little Bit Of Heaven and of course the title song. These are a staple for St. Patrick's celebration in America. Remember these classics are of American origin, they were written for the musical plays Olcott starred in, but have endured so that they've become pure Irish out of love.
Note in the film that Olcott is identified as a performer and that is more correct than to say he wrote these numbers. Back in the day before the founding the American Society for Composers, Authors, and Publishers it was common for songwriters to give copyright credit to a performer to cut him in on royalties for the sale of sheet music which was the venue by which popularity was measured. Al Jolson was the performer who most frequently used that practice.
The film messes somewhat with the facts, but does get the basic story of Olcott's life down with him marrying Arlene Dahl a hometown girl from Buffalo. Olcott did in fact get his first theatrical break as the leading man for Lillian Russell played here by Andrea King. And he did succeed William J. Scanlon as the most popular singer of Irish ballads and Scanlon is played by William Frawley. I'm reasonably sure no one is around who saw Scanlon perform.
Morgan was never in better voice than for this film. The musical numbers are staged well if not in the opulent style of Busby Berkeley. All in all My Wild Irish Rose is an enduring classic, no St. Patrick's Day would be complete without it.