He replaces Damian McGrath, who has moved on to the Rugby Football Union National Academy and will be working with the England Under-19s.
"Phil is a very intelligent rugby player who has a great understanding of the game," said England Sevens head coach Mike Friday.
"From a coaching perspective he will be successful as he is a very charismatic character who communicates well with players of all ages. It's very good news for the sevens squad."
Greening was forced to retire after failing to recover from a toe injury he suffered playing for Wasps in their Premiership Grand Final victory over Leicester at the end of last season.
Greening was a central figure as England established themselves as one of the major powers on the International Rugby Board Sevens circuit and he captained his country at the 2002 Commonwealth Games.
"I have always enjoyed playing sevens and am excited about my new role with the squad," he said.
"This season promises to be fantastic with the Commonwealth Games and the 30th anniversary of the Hong Kong Sevens."
England are seeded third for the Commonwealth Games in Melbourne and were pooled with hosts Australia in a tough draw on Thursday.
England should qualify in the top two from Pool C - which also features the Cook Islands and Sri Lanka - but they are then likely to face either Samoa or South Africa in the quarter-finals.
"That isn't necessarily a bad thing as to win any tournament you have to beat everyone you face anyway and we need to prepare for the Games knowing that we have to win every match," said Friday.
"Australia do have a fantastic sporting tradition and tend to raise their game when they play on home soil and they won't be easy to beat."
Australia coach Glenn Ella, meanwhile, is looking forward to "an old-fashioned Ashes-style showdown".
Commonwealth champions New Zealand, who won their sixth IRB Series title last year, are top seeds with World Cup-winners Fiji second.