John Durkin went missing in the early hours of Friday morning in central Rome’s Campo de Fiori neighbourhood.
His body was found a day later by Italian authorities, the US embassy in Rome said in a statement.
Durkin died after being hit by a train between the San Pietro and Trastevere stations to the west of the Tiber River, Italian media reported.
An economics student at Bates College in the north-eastern US state of Maine, Durkin was in Rome as part of an exchange programme through Trinity College in Connecticut, a state north-east of New York city.
Durkin was one of 55 American students taking part in the Rome programme, along with five others from Bates.
He was described by Trinity President James F. Jones as “an exemplary young man and a student-athlete in the truest sense of the word.”
Mark Harriman, Durkin’s football coach at Bates, said Durkin’s “commitment to excellence in all phases of his life was inspirational to the other members of the squad.”
In a brief statement the student’s family thanked “everyone for their support during these past few days.”