Along with Denis Hickie, he has been an inspiring force in the Irish back-line and has been staunch in both attack and defence. His play making and game breaking have made him a marked man in the tournament, and one opposition teams including Australia will be worried about.
The 29-year-old Bath player didn't start playing rugby until he was 17, but that hasn't stopped the Bristol-born Irish man becoming one of the most impressive centres in the northern hemisphere game.In fact, until his late teens he preferred soccer to the oval ball sport.
"I had played the game at 10, but you don't know what you are doing then, do you? Some people would say I still don't know. I didn't play rugby at my local school, Lockleaze, because they'd had a fight in a rugby match a few years before in which one of the guys broke his back. The school banned it, so we played football."
The professional rugby life suits him. Before, juggling work and a playing career was hard work. "I worked for a civil engineering firm, 60 hours a week, laying kerbs. I was working 12 hours a day, training at night and getting home at 9pm. The only thing I was fit for was bed. I would get up the next morning and it would be the same routine again."
In an interview with The Irish Times last year he told how, on Saturdays he used to work in the mornings, get picked up by one of the lads and go play a match for Bristol.
"Since the game turned professional I haven't looked back. At one stage I was working all the hours God sends. Now I have the chance to do something that I love and enjoy. You don't get that every day, so I'll make the most of it."
His Irish debut came in November 1997 against New Zealand in Lansdowne Road. It was only earlier that year that the IRFU had even become aware of his eligibility to play for Ireland through an Irish grandfather.
Selected on the wing for the following international against Canada, Maggs grabbed his first international try. An injury to Rob Henderson allowed him switch to his favoured position of centre for the Italian match and he remained an ever-present member of the team through the Five Nations Championship in 1998.
He came back to find himself out of a job, though, when his club Bristol went into receivership. The talented youth was soon picked up by Bath, however, which is where he has remained.
A fractured cheekbone ended his 2000/01 series early and ruled him out of a place on the 2001 British and Irish Lions tour to Australia. But he has been a constant in Eddie O'Sullivan's Irish squads and like a good wine seems to be getting better with age.
He agrees, half-embarrassed, but puts much of his improved performances down to the coaching staff, excellent support from the IRRU, and to his teammates.
I just want to do my job and do well for Ireland, and I'm not really bothered what everyone else thinks. I'm just worried about what my teammates think and what the Irish management thinks.
He celebrated his 50th cap earlier this year in the Six Nations grand slam decider against England. To mark the occasion he marched the Irish team out on the Lansdowne Road. The game is one most Irish supporters would prefer to forget, but Maggs had the game of his life. He was in fact one of the only Irish players to hit top form that day.
Going into the weekend's game, he is one half of an Irish centre combination that has the Australians worried. His waltzing partner, Brian O'Driscoll, is world class. I've been playing alongside what I consider to be one of the best centres in the world, if not the best. It is certainly a pleasure to play along side him. He's fantastic, he's a great player and a great friend. He expects things from everyone, he expects people to do their job and he expects the best from everybody. That's the standard we have to get to if we are going to be successful
Ireland faces into tomorrow's game without any pressure. They have qualified for the quarter-finals and avenged their 1999 defeat. They will run out tomorrow morning at 9am Irish time onto a pitch in Melbourne with the hopes and dreams of a nation. They are going for a win, but will be doing so without the added pressures of expectationor qualification on their backs.
It was a very different story last Sunday though. "Argentina was a big game for us, we were just relieved we can go into playing Australia full of confidence.
I think there was a lot of pressure on everybody to be honest. The build up was going on for weeks, and there was obviously pressure during the game, the Argentines are a strong physical team and we knew we couldn't give them too many penalties. We always knew it was going to be close and we're just relieved we came out winners in the end.
While the pressure might be off Ireland, the thousands of supporters heading to Melbourne will be hoping for a win. And Maggs believes the team can deliver one.
Yeah I do, I do think we can beat the Aussies. There's a lot of pressure on and they're obviously worried. They are the world cup winning side and there's expected to win, but certainly we're going to take the game to them on Saturday.
The Irish support has not gone unnoticed in the Irish squad either, according to Maggs. It's unbelievably important, it was such a big lift for the lads when we arrived in Sydney and it hasn't stopped since. The support in Adelaide was fantastic. Everyone's excited and looking forward to all the fans in Melbourne, and they're all hoping we beat Australia.