The 40-year-old former Bradford Bulls boss has signed a contract until the end of the 2025 season.
Smith , who joins Rhinos from reigning Queensland Cup Champions Norths Devils, is son of former Hull and Bradford coach Brian Smith and the nephew of former Leeds team boss Tony Smith.
He said: “I am excited about the opportunity and really looking forward to getting back to the UK.
"The opportunity to be a head coach in Super League is something I have always aspired to do and especially with a club with such a rich history in the game and a proud tradition of developing talent through their academy.
"As a development-minded coach, when I look back on my career the clubs I have enjoyed working at most are those who develop their own and I know that is part of the Rhinos way."
Smith added: “One of the best things about rugby league is the relationship you build with your players and I am looking forward to reconnecting with a number of guys I have worked with previously who are now at the Rhinos, but also I am excited about meeting and working with everyone else as well.
“I love coaching and helping players, young and old, to get better.
"As a coach you want to help them in their journey in their footy and in life and I am really looking forward to getting over to Leeds and starting to work with the guys."
Rhinos chief executive Gary Hetherington said: “We are extremely pleased to have secured one of the most exciting young coaches in the game at present.
"Rohan Smith is highly regarded both here in England and Australia and is someone who is passionate about coaching and most importantly for us, excited about developing our players and a winning culture and environment."
He went on: “I would like to thank Norths Devils and Brisbane Broncos in allowing us to speak to Rohan about our vacancy.
"I know both clubs rate Rohan extremely highly, not just because of his coaching philosophies, but how he has transferred that into a winning team at the Devils.
"At the outset I stated this was one of the most important appointments in our club’s history.
"I would like to thank all our supporters and partners for their patience during this period but it was vital that we spoke to all interested parties both here in England and overseas.
"Through that process, Rohan Smith was an outstanding candidate for the role and I am personally delighted to have agreed the deal to bring him to Headingley. "
Explaining his thinking behinsd the appointment, Hetherington stated: “Interestingly, Rohan is three years older than his uncle Tony when he became head coach of the Rhinos back in 2003 and I see many parallels in both their early coaching careers to this point.
"Rohan has vast experience having been part of various coaching teams over the last 29 years, working with people some of the biggest names in modern NRL coaching.
“We had two over riding criteria when selecting our new head coach.
"The first was that they must have had experience and success as a head coach and secondly have experience of working at the highest level in Super League or the NRL and Rohan fits the bill on both those fronts.
“Finally, on behalf of everyone at the club, I would like to thank Jamie Jones-Buchanan and the rest of the coaching staff for the outstanding job they have done in difficult circumstances in recent weeks.
"Jamie will remain in charge of preparations for the team for our next two games against Toulouse and Hull KR to give the side continuity and stability for two crucial games and we hope to have Rohan with us as soon as possible once the relevant paperwork has been completed."
Smith began his career as a video analyst at New Zealand Warriors in 2003.
He then moved to England to work with London Broncos before a return to Australia in 2007 to become an assistant coach with Newcastle Knights, working alongside his father.
He had a brief spell as head coach of Tonga during this period before moving to Sydney Roosters between 2010 and 2012.
In 2013, he moved to Penrith Panthers before a return to the New Zealand Warriors in 2014.
In 2015 he moved to Gold Coast Titans as an assistant-coach before the opportunity arose to become head coach with Bradford Bulls in the Championship.
After Bradford, he joined Norths Devils, who are a feeder club for Brisbane Broncos, leading them to a Grand Final win over Wynnum Manly Seagulls last year.