Leeds Rhinos head coach Brian McDermott says there is no player to rival Kevin Sinfield in the modern rugby league era, following confirmation of a switch to union at the end of the season.
Rhinos prop Jamie Peacock has also paid tribute, calling the 34-year-old the "greatest Super League captain".
Former England captain Sinfield will leave Rhinos to join Yorkshire Carnegie in November.
"Unparalleled, inspirational, a player to be envied," McDermott said.
Sinfield made his debut at 16 and has since won six Grand Finals, three World Club Challenges and a Challenge Cup for his one professional club.
"He's been in so many finals, led from the front and been more successful than most other players that have ever played the game," McDermott added.
"In this current landscape of a salary cap era, he's the most successful captain of the most successful team in Super League. They're things you don't rattle off easily."
Former Man of Steel Peacock, 37, another former England captain who is retiring at the end of the season, said: "He is the best captain of the Super League era and I think he is certainly in the top five players.
"What stands him out is his professionalism, self-discipline and durability.
"He has been successful as an individual and as part of great teams - and he steps up when it matters in the big games.
"What sets him apart on the field is his ability to stick to a game plan - he is nerveless under pressure.
"When big matches come up, he thrives, leads from the front and produces a big performance."
McDermott took over as Rhinos boss from Brian McClennan in 2011, and with Sinfield at the helm enjoyed a brace of Grand Final wins.
Last season's Challenge Cup victory against Castleford ended the Oldham-born playmaker's career-long wait for a winning playing appearance at the seventh attempt.
With that box now ticked, the hunt for a new challenge will take him to familiar territory, still at Headingley but under a new set of rules in a different sport.
|Danny McGuire on Kevin Sinfield|
|"Kev's a good mate more than anything. We play together in the halves and we've even been caught kissing each other on camera which is embarrassing," McGuire told BBC Sport.|
|"We've had some arguments as well, but every game that's important and means something, Kev always steps up to the plate.|
|"What Kev has achieved in the game is second-to-none. Loads of factors make him a great player but more for me he's a great team-mate and a great pal."|
"The fans have been absolutely awesome with me during my time but I just felt it was the right time," Sinfield told BBC Radio 5 live.
"There's obviously a synergy there between both rugby codes. I've always been a fan of rugby union. It's something that I've always wanted to do.
"I didn't want to have any regrets. I've been very fortunate to spend my whole career at the Rhinos and I'm very thankful for the relationships and some of the friendships I've made along the way and those will remain."
With Peacock also heading for new challenges as football manager at Hull KR, Ryan Bailey exiting last winter and long-serving prop Kylie Leuluai also moving on at the end of the year, the crop of players that helped to drive Leeds' 'golden decade' is slowly being broken up.
Rob Burrow, Jamie Jones-Buchanan and Sinfield's half-back partner Danny McGuire are the only survivors currently contracted beyond the current season, as new blood is introduced into the Rhinos fold.
"It's the cycle. We've been fortunate to play at a brilliant club for so long, but none of us would take things for granted," McGuire told BBC Sport.
"But the club are planning. There are some good young players coming through the system. They're getting more experienced, Brad Singleton, Stevie Ward and Liam Sutcliffe, hopefully they're going to be the players to take the club forward."