The move also deepens the Highlanders’ ties to the Tasman Mako and the men from the Deep South will hope that Christie can introduce the defensive starch that has been evident in the Mako's play over the past two seasons.
“Obviously I am stoked to be able to work alongside Brownie, Derms and Flutes,” the 35-year-old said in a statement.
“The chance to coach defence for the Highlanders is an awesome opportunity and I can’t wait to get to Dunedin and get stuck into our work.
“It’s already been a big year and this is a great way to finish it for me”.
As player, former Tasman, Highlanders and Māori All Blacks flanker, Christie was hard-nosed and relentless on defence, and Brown said he was attracted to those qualities.
“Naturally I knew Shane as a player and even then I suspected he would make a good coach,” Brown said.
“He is diligent, driven and most of all very passionate about the Highlanders. I’m sure he will slot into our coaching team very well he already has a good working relationship with Clarke at Tasman.
“A lot of defence is about attitude and Shane has a very competitive attitude and he loves to win.
“In other words he hates to lose, which I like as a motivating factor.”
The Highlanders were looking for a defence coach after the departure of former head coach Aaron Mauger, with Brown taking the top job.
The Highlanders' longer-term plan is to prepare Dermody to take over from Brown in 2023, so Christie's knowledge of forward play was another attraction.
Highlanders CEO Roger Clark said he was confident that Christie, although relatively inexperienced, could achieve “special things".
“Even though we had a lot of quality candidates it was clear to us that Shane had what it takes to deliver for us in the specialised area of defence,” Clark said.
“He is an up and coming defence specialist and we believe he can go on to achieve special things in his coaching career. We are delighted to have him aboard.”
Christie will already be familiar with several Highlanders players, with Mitch Hunt, Fetuli Paea, Pari Pari Parkinson and Shannon Frizell playing their provincial rugby with the Mako, who won their second Premiership title in a row on Saturday.
The Highlanders will announce their Super Rugby squad for 2021 on Thursday morning and Liam Squire's potential return will be one point of interest.
Squire, another Tasman player, has already had a meeting with Brown but is on the comeback from knee and hip surgery, which could complicate a possible return to Dunedin.
On Sky's The Breakdown show on Tuesday, Brown also revealed he had pursued big Auckland wing AJ Lam, but missed out to the Blues.