The Great Britain international, 19, has joined AC Fafe, who play in Portugal's top division.
"I'm really looking forward to the challenge. I'll be competing with some of the best in Europe," said Da Silva.
England Handball has supported the programme since the GB team lost its UK Sport funding after London 2012.
After a break of two years, and unable to go through the Rio Olympics qualifying process, GB men returned to the international stage in June 2015.
The GB men's team is now overseen by England Handball and the women's side is run by Scotland Handball.
England Handball CEO David Meli said: "Josh is an example of the great strides forward handball has made in this country over the last five years.
"Legacy was a buzzword of London 2012 and Josh is a true example of that legacy."
Josh da Silva has become the first player from England Handball's post-London 2012 performance programme to turn professional.