The 31-year-old — scorer of 53 goals in 119 appearances for his country — told Southgate of his decision during a phone conversation.
“Having already thought long and hard, I told Gareth that I had now decided to retire for good from international football,” said Rooney in a statement sent to Press Association Sport.
Rooney made his major tournament debut aged 18 at Euro 2004 and scored four goals in the tournament, but broke a bone in his foot during England’s quarter-final exit to hosts Portugal.
England have yet to progress beyond the quarter-finals of a major tournament since Euro 1996.
In his statement explaining his decision to retire from international football, Rooney said: “One of my very few regrets is not to have been part of a successful England tournament side.
“Hopefully the exciting players Gareth is bringing through can take that ambition further and I hope everyone will get behind the team. One day the dream will come true and I look forward to being there as a fan – or in any capacity.”