After private lessons, he made his debut in 1990, as Pinkerton in Madama Butterfly in the small German city of Fürth.
He made his American debut in 2004 as Dick Johnson in Puccini's La fanciulla del West at the Seattle Opera.
On 10 December 2006, he was thrust into the media spotlight in Franco Zeffirelli's new production of Aida at La Scala, which opened the theatre's 2006–2007 season.
During the second night of the run, Palombi took over the role of Radames when Roberto Alagna walked off the stage after booing from the loggione (opera fans who sit in the less-expensive seats at the very back of the Scala).
Palombi, his understudy, entered on stage wearing jeans and a black shirt to finish the act, and returned in costume after the interval to sing the remainder of the opera.