The 27-year-old, who is currently on the sidelines with a back injury, has extended his terms and will now stay on until the end of the 2019-20 campaign.
"I'm extremely happy and proud to have re-signed with Edinburgh, at a time when the club is heading in a very positive direction," he said.
"The team's success is spearheaded by an excellent management group and I'm looking forward to contributing to help make the club as successful as possible."
Head coach Richard Cockerill has been impressed with the former Bath man's impact at the club and is pleased to have tied him down long term.
He said: "We're delighted that Darryl has committed his future to the club.
"He's been an influential character since arriving in the summer and he's got a major role to play in the seasons to come."