Greening helped guide England to the Silver Medal at the Commonwealth Games in Melbourne and to second place in the HSBC World Sevens Sevens after previously captaining his country on the same circuit.
He takes over from Graham Shiel, who moves to a skills coaching role, and becomes the third high-profile Englishman to currently be involved with senior Scottish sides after joining Andy Robinson and Neil Back north of the border.
"This is a really exciting time to be joining Scottish Rugby and their developments in Sevens rugby. I can't wait to get started and back onto the circuit," said Greening, who was in line for a spot on the Lions' Test bench 11 years ago before injury robbed him of that opportunity.
"I want to cement the Scotland 7s team as one of the core competitors in the abbreviated game and help produce some exciting new Scottish rugby talents ahead of the 2014 Commonwealth Games and 2016 Olympics."
After leaving his Sevens role with England five years ago, Greening spent three years with London Welsh in the RFU Championship before departing Old Deer Park in 2011.
The 36-year-old was linked with the head coach job at Nottingham earlier this year but will now turn his attentions to improving Scottish Sevens as Glasgow gears up to host the 2014 Commonwealth Games.
Greening has signed a three-year deal with the SRU and the Murrayfield hierarchy are confident they will see big improvements in the coming seasons.
"We're delighted to welcome Phil into this new role. He brings with him a wealth of international coaching and playing experience," said Scottish Rugby's director of performance rugby Graham Lowe.
"His passion and understanding of Sevens is clear and he has taken every opportunity to remain at the forefront of developments in the game after his time with England Sevens.
"He will be a key part of helping us reach our goals at the 2014 Glasgow Commonwealth Games, and before that at next year's Rugby World Cup in Moscow. He will also drive our players to stake a claim for inclusion in the Great Britain Sevens team in the 2016 Rio De Janeiro Olympics".