It's not often that a 23-year-old superstar moves on from his lifelong sport in pursuit of another endeavor a continent away, but in the case of Louis Rees-Zammit, it wasn't much of a decision at all.

Instead, it was the realization of a childhood dream.

"This was my dream since I was a little boy. [It was] to play in the NFL, and to join a team like this is incredible," Rees-Zammit said. "I'm incredibly proud of the journey I've been on."

Indeed, it has been quite the road for Rees-Zammit, who scored 14 tries (which are essentially touchdowns) in his career for the Welsh national team. A professional since he was 18, Rees-Zammit has competed in multiple "Six Nations" tournaments and the 2023 Rugby World Cup. He also stared for Gloucester of Premiership Rugby.

It's all to say that Rees-Zammit was among the top young rugby players in the world heading into 2024, but his lifelong dream of playing professional football remained. By January, rather than preparing for another year of rugby, Rees-Zammit announced that he was making his long-contemplated leap to the NFL.

Only a few months later, after training through the International Player Pathway (IPP) program, the former rugby star was already making an impression as a newly-signed member of the Kansas City Chiefs.

"He's so diligent with everything and wants to be so good at everything," said Head Coach Andy Reid during rookie minicamp. "I've appreciated that. You can see the progress he's made."

Rees-Zammit's love for football began with his father, who played in the British American Football Association in 1987. That passion for the game extended to a young Louis, and after years of staying up late to watch the NFL while in Wales, Rees-Zammit is now part of the very league he once followed from afar.

There's still plenty of work to do, however, and he still needs to make the team, but the challenge of jumping from one sport to another has been something that Rees-Zammit has embraced with the same tenacity he once showed on the rugby pitch.

"I think it's just learning all the plays. It's so different from what I'm used to," Rees-Zammit said. "Obviously, in rugby, you don't have to learn as much, but I think physically, I'm in good shape…The biggest difference is just mental. It's [about] staying on top of things, staying on top of the playbook and making no mistakes."

There's no denying Rees-Zammit's physical ability, as his 4.44-second 40-yard dash at an IPP workout earlier this year would have ranked fifth among all running backs at the 2024 NFL Scouting Combine. It's the mental element, as Rees-Zammit indicated several times following practice on Thursday, that will likely be his biggest hurdle moving forward.

"I'm non-stop trying to learn this playbook, because as soon as I can stop thinking and can just play fast, that's the biggest thing for me," said Rees-Zammit, who added that he spends two hours every night studying the playbook following team meetings. "I'm playing catch up with a lot of people who have played American football since they were little kids. There's no time to rest for me. I have to give this my all because ultimately, this is my dream. To make it come true, I have to be a step ahead of a lot of people."

A telling checkpoint for Rees-Zammit and his readiness to play in the NFL will be the Chiefs' first padded practice, which will take place later this month. The offseason training program was devoid of any "live" contact, meaning that Rees-Zammit has yet to absorb a hit at the NFL level, but he's eager to show that he can handle it.

"I'm excited. I can't wait to see the difference. I get that question all the time. What's harder-hitting, rugby or American football? We'll soon find out," Rees-Zammit said. "It's going to be fun. I've played a contact sport since I was 12 years old. That's bone-on-bone, but we'll see what it's like when it comes to pads."

Another interesting wrinkle in this story, and one that may prove to be an enormous opportunity for Rees-Zammit, is the league's new kickoff format this season. The rules, which are similar to those used in the XFL, will dramatically alter the strategy on kickoffs in 2024, and ironically enough, the play now somewhat resembles the look of what takes place in a rugby match.

"This kickoff rule is new, so no one knows what's going to [happen]," Rees-Zammit said. "We do have some creative plays, and I'm not going to mention them now, but hopefully you'll see them in the preseason. I'm just giving it my all on the field and [trying to] be the best player and person possible for the team."

Additionally, Rees-Zammit has demonstrated the ability to not only return kicks, but also to deliver them himself. He was rotating in as a kickoff specialist throughout offseason practices this summer, potentially providing the Chiefs with another defender in coverage in place of a traditional kicker.

"Louis has done above and beyond what I expected," said Assistant Head Coach / Special Teams Coordinator Dave Toub back in May. "He can kick field goals and he can be a kickoff guy for us – he's every bit as good as [safety] Justin Reid is in terms of moving the football on kickoffs."

It's all about being as versatile as possible for Rees-Zammit, and whether it be contributing on special teams or on offense as a running back, he has clearly embraced the mantra of doing whatever it takes to make the Chiefs' roster in 2024.

There's still a long road ahead, but if one thing is certain, the rugby star turned professional football player is going to do everything he can to make his childhood dream become a reality.

"Everything is completely different. It's a completely different sport," Rees-Zammit said. "I'm just trying to learn as much as I can, [I want] to bring what I've [learned] from rugby to American football, and just give it my all."