The experienced Australian, 52, arrives at KCOM Craven Park with immediate effect and initially until the end of this season.
Smith has been out of the game for 18 months since leaving his last role as Warrington, saying at the time that his interest in rugby league was “dwindling”.
However, the man who led Leeds to two Super League titles including their first Grand Final glory in 2004 is now refreshed and ready to return to the game, tasked with firing the Robins back up the table.
They sacked his fellow countryman Tim Sheens last night with KR having won just five of their 16 league games so far and losing Friday’s Challenge Cup quarter-final against Warrington.
They are just two points above bottom-placed London Broncos and host champions Wigan Warriors on Sunday when Smith will take charge for the first time.
Smith, who coached England at the 2008 World Cup and won the Challenge Cup three times with Warrington, said: “It’s a great opportunity for myself to get back in and start coaching again.
“I’ve had a good break and I’m very excited to be working with the talent available at Rovers.
“I’m keen to get on board with the players and understand where they’re at and see where I can help them.
“It’s been a whirlwind couple of days for myself, but I’m very excited about the opportunity.”
Smith, whose coaching career in England began with Huddersfield Giants in 2001, added: “I want to help the players to be as good as they can be both individually and as a team.
“I want to instil some confidence in areas where it’s needed and practice in those areas too.
“With the talent available, there’s a good, strong chance of climbing the ladder to a place which is far greater to where we are at this moment.
“I’m looking forward to that journey and development of players.
“I’ve had a lot of experience over the years at all the clubs that I’ve been at, where they haven’t been in ideal situations when I’ve taken over.
“They ended up in strong positions once I left and I look forward to doing exactly that in this period of time."
Smith twice won the League Leaders' Shield with Warrington and led them to three Grand Finals, although he never repeated his Rhinos Old Trafford feats with the Cheshire club.
On Rovers, he said: "There’s a lot of players that I admire within the team, what they do, but it’s now up to me to get the best out of them, as well as getting the best out of one another.
"That’s what a team is about. I want to get the boys in a position where they’re proud of what they’re producing and I think we can do that quickly.”