Dan Ashworth is "delighted" Declan Rice has pledged his international future to England following his attempts to influence the 20-year-old's decision.
West Ham midfielder Rice, who has won three caps for the Republic of Ireland, announced he had switched allegiances on Wednesday.
Former Football Association technical director Ashworth confirmed he held talks with the player about the situation before leaving his role to take up the same position at Premier League club Brighton.
"You've got a young man who has clearly given a great deal of thought to where his international career is going to go. It's been a really difficult decision for Declan and his family," said Ashworth, who left the FA this week to start work with the Seagulls.
"I know he's spent months deliberating on it, no secret from the fact that he met England and Ireland to discuss his future.
"Obviously he's liked what we've had to say and wants to push his allegiance towards England and the team.
"He's decided he wants to play for England and he's English. As an Englishman, I'm delighted about that."
London-born Rice represented the Republic from under-16 level after qualifying through his grandparents, with all three of his senior appearances coming in friendlies.
Last summer, he said he needed time to decide his international future as winning a competitive cap would have tied him to Ireland.
While he was part of the conversation, Ashworth believes England manager Gareth Southgate was a more significant influence on Rice.
"Ultimately, the player wants to hear from the manager," he added.
"I didn't pick the team, the people that pick the team are the managers and they are the ones that will ultimately decide whether the player plays or not so that's the main conversation.
"So Gareth would have been the most important cog in that wheel."
Brighton manager Chris Hughton, who Ashworth is now working with at the Amex Stadium, was in a similar position during his playing days.
Born in London to an Irish mother, the 60-year-old won 53 caps for Ireland between 1979 and 1991 and represented the country at Euro 1988 and the 1990 World Cup.
He feels only time will tell whether Rice has made the correct choice.
"My situation would have been similar. I was asked by the Republic of Ireland to represent them and I jumped at the chance. There wasn't that England opportunity there for me," said Hughton.
"That's different with Declan where he has the choice between the two and it's obviously been a very difficult time for him.
"Someone who played for the Republic for so long and was also on their coaching staff for three years, I think it's a big miss for us and a big miss for a Republic of Ireland squad that has found it harder in recent years in the level of player that they are able to bring through, so I think very, very disappointing.
"Whether he has made the right decision, no-one will know until he gets later into his career and sees how many England caps he has."