One of the more memorable moments of Mayor Martin J. Walsh’s inauguration ceremony at Boston College’s Conte Forum on Jan. 6 occurred during a musical interlude featuring Yo-Yo Ma, the 59-year-old Chinese American cellist who lives in Cambridge. Many in the audience anticipated that Ma might seek to tickle the mayor-elect’s Irish heartstrings, given that the official program book promised a “traditional Irish melody” as part of his medley, which also included George Crumb’s Toccata and Bach’s Cello Suite No. 3.

As he took the stage, more than a few boyos in the forum were elbowing each other with wisecracks of the “Yeah, Marty’s a huge Yo-Yo Ma fan” variety. But, when Ma eased into his interpretation of the mournful ballad “Danny Boy” — the smart talk ceased and the deep breaths began.

On stage, Walsh and his family— especially his Galway-born mom Mary— beamed. “I never expected him to play the song,” Mary Walsh admitted later. “I got very emotional, I really did. And I thought he did a beautiful job with it.”

Neither Mrs. Walsh nor her late husband John would have heard the song much in their childhood on the rocky roads of Connemara. “Danny Boy” was — after all— penned in 1910 by an Englishman, Frederick Weatherly, a lawyer who dabbled in literature and songs. It wasn’t exactly a Top 40 hit in Ireland— at least not in its current incarnation. But the melody that the words are set to are quite clearly Irish in origin, according to Brian O’Donovan, host of WGBH radio’s Celtic Sojourn program.

“It became known as Londonderry Aire, but it likely predates that even. It’s likely an old, old Irish aire that was collected by various people, like harpers who travelled around to the old houses in Ireland,” explains O’Donovan. In County Cork, where he grew up, the exact same melody was used for a different song, “Morning in Beara,” a reference to the peninsula of the same name which is the ancestral home for many Irish Bostonians.

But it’s “Danny Boy” that has been adopted by millions of Irish-Americans, some of whom no doubt interpreted it as a “rebel” song — or one that spoke to the ever-distant gulf between ancestral homeland and the far-flung diaspora. In that vein, Ma’s selection was just right for this Boston audience and occasion.

“It has become such an iconic representation, so whoever chose it [for the inaugural performance] chose it well. It represents an Irish-American aire and it’s immediately recognizable. That in itself makes it the right choice and a touching tribute,” says O’Donovan.

Kate Norton said that Yo-Yo Ma was recruited to perform by “friends of the mayor” who were involved in the inaugural planning and had worked with Ma at other special events in the past. “[They] had connections to Yo Yo Ma through that history, they invited him to perform, and he said yes.”

When asked about the song choice this week, Mayor Walsh said Yo-Yo Ma made the call. “I think he picked it himself, the song,” Walsh said, referring to Ma. “He was whispering back to the family, he was saying, ‘This is for you guys.’ When he played the second selection, he said, ‘This is the campaign, during the election.’ And then when he got toward the end of it…when it was nice and relaxing, he was like, ‘this is the victory.’ ”

Reporter news editor Gin Dumcius contributed to this report.