The former Lornshill Academy pupil took his first steps in rugby with Alloa and Stirling County RFC before being signed to the Edinburgh Rugby's elite development (EDP) programme.
The stock of the former age-grade internationalist rocketed after his return from an 18-week spell with the Canterbury RFU, as one of the recipients of the John MacPhail scholarship.
The big second-row started 23 of 26 appearances in his debut season, including starts in all but one of the club's historic run to the 2012 Heineken Cup semi-final.
Gilchrist, who added to his four Scotland caps in the recent viagogo Autumn Tests with a start against Australia, has already racked up 58 outings for the club and was thrilled to extend his stay in the capital.
"I'm absolutely delighted to sign on here again," said Gilchrist.
"It was an easy decision to make. The new coaching team and this group of players make the club a really good place to be. I think we're heading in the right direction with the right personnel in place to ensure that continues.
"This is where I started my professional rugby career and I certainly see no need to look elsewhere.
"We were disappointed with how last season went but elements of the season before were really good. Our Heineken Cup run was really special and something I want to do again with this club."
He continued: "It's a big ambition of mine to force my way into the Scotland squad. I don't think I'm there yet by any means but Edinburgh Rugby is where I think I'll perform at my best.
"I like to think that I'm always progressing, week on week, month on month.
"Being here is going to make me a better player, and has made me a better player already."
When asked if the new deal gave him a lift going into the inter-city derby, he smiled in reply and added: "I don't need a lift for this game. I can't wait for the Glasgow derby.
"Obviously I'm over the moon to have signed again but there's no lift needed for these games."
Edinburgh Rugby head coach Alan Solomons was equally pleased that the big lock was set to be part of his future plans.
He said: "This news is absolutely fantastic for us.
"Gilcho [Gilchrist] is an outstanding young player. I think he is going to go on and play many, many Test matches for Scotland.
"It's great to have another Scottish international come through like this and I think it's massively important that he stays here with us at Edinburgh Rugby."
The deal means Edinburgh Rugby continue to retain the top Scottish players at a club which features 16 senior Scotland internationalists among the 43 players eligible to represent the country.
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