The 28-year-old defender joined Villa on a three-year deal from Bournemouth on Monday to become Di Matteo's first signing since taking over the club earlier this month.
The 28-year-old centre-back, who has penned a three-year deal with the West Midlands side, previously captained Bournemouth to promotion from both League One in 2013 and the Championship in 2015, and that experience is expected to prove invaluable to his new club's bid to make an immediate return to the Premier League.
Di Matteo has also tasted success in the second tier before, having taken West Bromwich Albion up in 2010 in just his second season in management, and the former Championship League-winning Chelsea boss is now planning an extensive summer rebuild in B6 after seeing Villa win only three league games last term.
Elphick arrives as the first piece of the puzzle, and the ex-Brighton & Hove Albion defender did not need much convincing to join his new manager’s claret and blue revolution once he heard about his ideas and vision for the future.
"I can’t wait to work under Roberto,” Elphick told avfc.co.uk. “The phone conversation we had, I came off the phone and thought 'this is the man I want to play for'.
“The gaffer sold me his ideas and vision for this football club, it didn’t take me long to decide that this is where I want to be.
“When he told me his ideas, I didn’t look back and for me, I was immediately looking forward and thinking about getting this club back to where it should be.”
Di Matteo will also have some respected figures assisting him on his backroom staff, having appointed Steve Clarke as his No. 2 and Kevin Bond as a first-team coach.
Clarke, who was sacked as Reading boss in December, guided West Brom to their highest-ever Premier League finish of eighth in 2013 and served as an assistant at Chelsea, Newcastle United, West Ham United and Liverpool beforehand.
Bond also brings a similar wealth of experience after working at Tottenham Hotspur, Portsmouth, Newcastle, Southampton, Bournemouth and Queens Park Rangers, and Elphick is looking forward to working with both of them once pre-season begins.
“There’s a lot of experience there,” he added to avfc.co.uk. “I have known Kevin for the last three or four years. He’s been coming down and watching us train at Bournemouth.
“Steve’s CV speaks for itself. He was a great centre-half as well so I am sure I can learn from him.”