The Washington native gained experience playing for the Ulster Ravens in the past two seasons, thanks to a link up between Trinity's director of rugby Tony Smeeth and Ulster Academy manager Gary Longwell.
He led Trinity to the inaugural IRFU All-Ireland Club Sevens title in May and played in the summer's Churchill Cup tournament, earning himself a place in the American World Cup squad.
LaValla, who only took up rugby at 16, has been named on the USA replacements bench for Sunday's Pool C clash at New Plymouth.
"I'm really looking forward to it," he told IrishRugby.ie, ahead of the match against Ireland. "Everyone I know over there is going to be watching it and I'm really excited.
"I know a few of the Irish players from my time with Ulster so I'm really looking forward to getting on and seeing what I can do on that stage."
The Eagles' meeting with Ireland will take place on the 10th anniversary of the 9/11 terrorist attacks and LaValla admits that it will be on the players' minds.
"A lot has been made of that and it's obviously a day that resonates with every American. We are going to commemorate the occasion - we're going to a service and we're going to wear some armbands in recognition of 9/11.
"It is an ever-present thing for Americans but we're very much focused on the game as well."
After five weeks' pre-season training with his new club in Paris, where he is on a developmental contract, LaValla has spent much of the past two months on national duty - something the 23-year-old says has brought the team closer together.
"The team chemistry is uncommonly good amongst representative sides from what I've experienced. We've got a very tight group of guys here which is great for what we have ahead of us.
"To finally have some time together is really rare for the Eagles because we're only really in assemblies twice a year."
According to both the IRB World Rankings and the pundits, the USA will be up against it when they face Declan Kidney's side. But LaValla is still hopeful that his team can cause an upset.
"You really want to hang in as long as you can. The longer you can frustrate a team that's overwhelming favourites, the more they'll start to kind of panic or start to lose a bit of their composure.
"Really the pressure is more on them than us so it does free you up to play. If you can get stuck in early, you never really know what can happen.
"There'll obviously be a lot of passion, given the day and given that it's the World Cup, so I would say the longer we can hang in, the more it will be to our advantage."
The underdogs' chances should be boosted by Eddie O'Sullivan's knowledge of the Irish set-up and LaValla says the USA's head coach does have a special game-plan in place for his former team.
"In the past he actually worked as forwards coach for the Eagles so he came with more of an understanding of USA rugby, the obstacles it faces and the types of players that we have.
"He's definitely brought a lot of structure and attention to detail, which I think is good. It’s good to have an experienced coach, a man of his background that can bring his wealth of knowledge to USA rugby players."
Follow the Ireland team in New Zealand on www.twitter.com/irfurugby.