Halfpenny was originally a member of the Ospreys academy who let him go because of concerns about his size.
He signed for Cardiff Blues ahead of the 2007-08 season and played for Cardiff RFC and the then Cardiff Blues between 2007 and 2014.
"I'll be forever grateful to Cardiff for giving me the opportunity to join the academy and start my professional career," said Halfpenny.
"I instantly felt at home and will always look back at my time at Cardiff as some of the most memorable years of my life."
During that seven-year stint, Halfpenny made 87 appearances and scored 568 points, winning the Amlin [now European] Challenge Cup and [now defunct] Anglo-Welsh Cup.
He signed for Toulon in 2014, winning the 2015 European Champions Cup with the French side before returning to Wales with Scarlets in 2017, spending six seasons in Llanelli.
Halfpenny travelled to New Zealand to join Crusaders in 2024 before linking up with Harlequins the following year.
After being involved as a kicking coach for Wales' summer tour of Japan in 2025, Halfpenny returned to Cardiff with a short-term contract in September 2025 as a kicking coach and player and that deal was extended until the end of the season.
He played his first game for the Blue and Blacks in 4,347 days when he faced Ulster in the win in December 2025 and also featured against the same opposition the following month.
That appearance off the bench in Belfast during the 21-14 defeat could be his final professional match, if Halfpenny is not involved in Cardiff's two remaining United Rugby Championship (URC) matches against Glasgow and Stormers or any further play-off games.
"It's a special club and to be able to finish my playing career where I started means so much," said Halfpenny.
"I have given everything to rugby, and in return, it's given me more than I could ever have dreamed of.
"It's never going to be easy to say goodbye but I'm finishing with an immense sense of pride and gratitude."
Former Wales and Lions full-back Neil Jenkins was Halfpenny's kicking mentor and hero growing up.
"I first met Leigh back in the academy days, as a young kid at the Ospreys," said Jenkins.
"All the way throughout senior rugby, we worked together. It has been a special bond.
"We've had a fantastic relationship. I've got a huge amount of respect for what he's done and been through.
"I try explaining to people that, often in life, those who are any good work incredibly hard. Maybe harder than anyone else. Leigh's one of those for sure.
"Seeing what Leigh is today, not just as a rugby player, but as a person more importantly for me, is special. It's been incredible seeing that journey."
Rhys Patchell was a regular room-mate of Halfpenny.
"I'm not sure there's much more to say about "Pence" than has already been said," said Patchell.
"The most diligent professional you could find, obsessed about squeezing every last drop of ability out of himself. World-class for almost two decades - it didn't happen by accident.
"Fearless in the air, brave in defence, smart in attack. I used to marvel at how, once he put the scrum cap on, it was like watching Clark Kent turn into Superman.
"People saw Leigh as the guy who always got the job done, but as his room-mate I got to see so much more than the rugby player.
"I got to know the incredible human he is."
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