The 46-year-old becomes the main man at Kingston Park following the dismissal of director of rugby Steve Bates.
Bates was relieved of his duties prior to the club's final game of the season this weekend after they narrowly avoided relegation to the Championship having recorded just six league wins in 21 matches.
Tait had previously worked underneath Bates but will now report directly to chief executive David Bell, with his first match in charge coming against London Wasps this Saturday.
"There will be some tactical shifts for next season, and that's something I will challenge the players with," said Tait, who was a try scorer in the Lions' historic first Test win over South Africa in 1997.
"I want to shift things slightly and add a few extra dimensions. It will be a challenge for the players to see if they are up for moving in the direction I am keen to take things - and if they buy into it, we can have everything ready for the start of next season. But if we have players dragging their feet then it will take a little bit longer.
"The guys already here are ready to do that I think, but it's their attitude and the attitude of new recruits that will determine how successful it will be."
Tait, who played in both the first and second Test victories 13 years ago and made a total of six appearances for Sir Ian McGeechan's tourists, has made it clear that he will have sole control of all playing matters in his new role.
The club have also stated that they will not be bringing in a new director of rugby and that Tait will instead be helped by current staff when it comes to off-field matters such as administration and contract negotiations.
The ex-Scotland back, who played centre as well as wing and had only just returned to rugby union from rugby league when he toured with the Lions, is determined to bring in a number of new players as he looks to bring a new style of play to the north east.
"We've got to get this game out of the way and then we'll sit down with the senior players to plot the course forward," added Tait.
"We have probably had too many bashers to be honest where ball-carriers are concerned, and we need to add a little bit more ball-playing ability and more subtlety to that arena.
"My phone's been ringing off the hook already, even in such a short space of time.
"There's a lot of players still looking for clubs, and the difficult thing always arises that you identify one player, and then you might hear about someone else being available, and then you have to weigh up which will be the right option.
"So that is a big extra thing for me to incorporate into what I do, but there's no need to panic and certainly no need to rush on the recruitment front.
"We're fairly far down the line on talking with a number of players and hopefully should be primed to make announcements on that front soon enough.
"New and different players are becoming available all the time, and that is not going to stop happening any time soon.
"Everybody always seems keen to have their recruitment sorted by Christmas it seems to me, but from my point of view there's no need to jump into things.
"We are pretty well-placed in a number of situations as I say, but there are also some other areas where we are still keen to keep pushing hard to see what is out there - and how we can strengthen the squad."