Alex Antetokounmpo signed a three-year contract with UCAM Murcia in Spain's Liga ACB.
The 18-year-old was unranked in ESPN's top 100, but had college offers from DePaul, Ohio and Green Bay.
"I don't really believe in pressure like that, but it's definitely a lot of expectations on you. And being the baby brother, it's a lot of being told what to do a lot of the times, but you've just got to take the criticism and move on," he said of being the younger brother of Giannis Antetokounmpo.
Antetokounmpo will be eligible for the 2021 NBA Draft.