The 24-year-old Marsh will make his debut for the senior Australia debut, when he appears in the Twenty20 International against West Indies on Friday at Kensington Oval.
"It's been fantastic, and obviously, I have been dreaming about this for a long time," he told reporters.
"Being over here and being in the changing rooms with all the guys has been fantastic so far, and I can't wait for the game to start. I feel the emotion. Obviously, I have been working hard, and I can't wait for the match to start, and to represent my country.
"This is a great opportunity for me, and I have got a chance on this trip to the Caribbean. I am looking forward to it. I have got to grab it with both hands and do all the things I have been doing right over the last 12 months. Hopefully, I can do well."
Marsh, the Western Australia Player-of-the-Year, is the son of former Australia opening batsman and national coach, Geoff Marsh.
"He gave me a bit of advice before I came over here, and told me to come over here and enjoy the experience, and enjoy being in this great team," the younger Marsh said.
"He has been pretty good to me. When I do need any advice, he has always been there for me. He has tended to let me work things out for myself, and stay away from my cricket which has been good. But whenever I need his help, he has been there."
Marsh was the most outstanding batsman in the cash-rich Indian Premier League, after distinguishing himself as the leading Twenty20 batsman in Australia's 2007-08 domestic season.
He transported his rich vein of form to India, where he propped up Kings Punjab XI's batting with 593 runs in 10 matches at an average of 74.12.
"The IPL was fantastic for me," he said. To get over there, and play a few games, and do well, it was a great lead-up for this trip to the West Indies.
"I am hitting the ball as best as I can at the moment, and hopefully, it can continue on this tour. But getting over here and learning as much as I can. I am not going to put too much pressure on myself.
"I am just going to go out there and enjoy playing with Ricky Ponting, Michael Clarke, and guys like that. It will be an honour to walk out on the field with them."
Marsh will be one of two players making their international debuts for Australia in the Twenty20 match.
Wicketkeeper/batsman Luke Ronchi will hold the gloves, as Brad Haddin continues his battle with a broken finger.
Australia however, have chosen discretion as the best part of valour, considering there are also five One-day Internationals to conclude the tour.
Haddin broke the ring finger on his right hand during the opening Test in Jamaica and battled with the injury throughout the rest of the series which led to Ronchi being flown to the Caribbean as cover, although he was not required in the third and final Test which Australia won to secure a 2-0 series win.
Australia have also rested Andrew Symonds, whose stiff back limited his appearance on the last day of the third and final Test, and Nathan Bracken, who is expected to be a key bowler in the ODI series.
West Indies have rested Chris Gayle for the match. He has been sidelined to allow the nagging groin injury that has affected him over the last two months more time to heal.
Gayle led West Indies in the third and final Test which the Aussies won by 87 runs, but team management have chosen not to give him a few more days to overcome the problem.
Uncapped opening batsman William Perkins will replace Gayle at the top of the order for the Twenty20 International.
West Indies may also debut uncapped batsman Andre Fletcher. The 21-year-old is one of the more talented batsmen in the Caribbean, and has shown his penchant for the shorter form of the game with outstanding performances in the Stanford Twenty20 Cup.
West Indies (from): Ramnaresh Sarwan (captain), Dwayne Bravo (vice captain), Sulieman Benn, Shivnarine Chanderpaul, Fidel Edwards, Andre Fletcher, Xavier Marshall, William Perkins, Kieron Pollard, Daren Powell, Denesh Ramdin, Kemar Roach, Darren Sammy, Jerome Taylor.
Australia: Ricky Ponting (captain), Michael Clarke (vice captain), James Hopes, David Hussey, Michael Hussey, Mitchell Johnson, Brett Lee, Shaun Marsh, Luke Ronchi, Shane Watson, Cameron White.