Speaking for the first time since he inked a three-year deal with the Bears, Horsburgh also revealed how he had been won over by coach Mal Meninga.
The 28-year-old has spent recent days in Perth preparing for his move at season's end, with the Bears to begin training at the WACA in less than three months.
His decision to move comes after 10 years with the Raiders, broken up only by a brief loan deal with Canterbury during the COVID-impacted 2021 season.
"I just felt like I needed a change, a bit of a refresh if you will," Horsburgh told the club's Big Bears podcast.
"I feel like I have so much more to offer. I am keen to show the Perth people what I can do.
"I can't wait for this move. My missus and family, we're excited.
"We've all seen what Canberra has to offer. I loved my time there, but I am ready for a change and ready to restructure my life."
Horsburgh became something of a cult hero at the Raiders and good enough to play State of Origin for Queensland when at his best.
But he also spent time in reserve grade in 2024 and drew the ire of Ricky Stuart earlier this month when sin-binned for a slap in a season-defining loss to Newcastle.
Stuart dropped Horsburgh the following week, but insisted there was no bad blood between he and the Raiders forward.
Horsburgh also paid tribute to Stuart in Friday's podcast, labelling Stuart a "very good coach and great bloke", who had taught him all he knew about the sport.
But ultimately, Horsburgh said it was another Raiders great who won him over.
The front-rower was immediately sold by Meninga's vision for the Bears, when the pair met in a Canberra cafe recently.
He then opted to hold off confirmation of his move to Perth until after last week's clash with Newcastle, which doubled as Josh Papalii's last home game.
"It happened quickly," Horsburgh, whose signing gives Perth's pack some impact, said.
"We talked a little bit, and then all of a sudden he flew to Canberra and had a chat with me and my girlfriend.
"He made me fall in love with the ideas he had around building a club.
"The way he was talking about Perth and footy in general, it seems like he knows a lot. I am very excited to have another chapter in my life and learn a lot."
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