The chick, named Garan - the Welsh word for crane - was reared on the Gwent Levels after its parents, known as Lofty and Gibble, nested there earlier this year.
The adults originated from the Great Crane Project, which has been reintroducing the birds to the West Country since 2010.
There are about 160 cranes in the UK.
The 4ft (1.2m) grey bird has a "sonorous call" which can be heard more than three miles (5km) away.
Damon Bridge, RSPB manager of the Great Crane Project, said: "These wonderful birds died out across the UK sometime in the 1600s, having been a favourite of the medieval dinner table.
"Seeing them spread back into their former haunts highlights the importance of protecting our wetlands."
Richard Archer, RSPB conservation officer for the Somerset Levels and the Severn Estuary, said:  "Although most of the released birds have now reached breeding age, this Welsh pair is one of only three that have successfully reared young this year, so they are really crucial to the project's long term success."
A Welsh-born common crane has taken to the skies of Wales, for the first time in about 400 years.