Northern Irishman McDowell erased a four-stroke deficit to force a one-hole play-off with American Webb Simpson before emerging victorious at the Harbour Town Golf Links in 2013.McDowell returns to the PGA Tour FedEx Cup event this week as a winner but the 2010 US Open champion is not living off past glories.
"Last year's win was great but it means nothing now," said McDowell, who missed the cut at The Masters last week.
"Now, we have to treat it like another event, prepare how we always do, execute our game plan and hope things go well.
"I'm looking forward to getting back and managing the expectations of a defending champion this year. I'm aware of the pitfalls and don't want to put too much pressure on myself."
McDowell added: "The Hilton Head area has always been on my radar and I feel like I can win here.
"It's a very nice course that tests every facet of the game, and it's stood the test of time. I'm excited to be coming back."
McDowell, who is looking to become the first player to win back-to-back Heritage titles since Boo Weekley in 2007 and 2008, leads a star-studded field in South Carolina.
Last year's runner-up Simpson was the last to commit to the tournament, which already boasts American young-gun Jordan Spieth.
The 20-year-old finished in a tie for second spot in his debut at Augusta, three shots adrift of winner Bubba Watson.
Jason Day, Charl Schwartzel, Luke Donald, Bill Haas, Matt Kuchar, Zach Johnson, Vijay Singh and Ernie Els will also be competing at the Sea Pines Resort.