Chalk faces no opposition at this point in the November general election for the seat, now held by Rep. JoAnne Gilham, R-Hilton Head. Gilham is stepping down at the end her third term because of a term-limits pledge.
Petition candidates have until July 15 to file. To be listed on the ballot, candidates must collect signatures from 5 percent of registered voters in the district.
Chalk claimed 63.2 percent of the vote, compared with Hairston's 36.8 percent, according to unofficial results. County officials will certify votes Thursday.
Out of 24,510 registered voters in House District 123, only 3,144, or around 13 percent, voted.
Chalk, who served in the North Carolina House of Representatives from 1985 to 1989 and in the North Carolina Senate from 1989 to 1990, said Tuesday evening that he did not expect to win by such a large margin.
"I expected to win or I wouldn't have run," Chalk said from his celebration with family and friends at the Yummy House restaurant on the island. "But I quite honestly am humbled by the margin of victory, and it's a testament of the hard work and the efforts put forward by a large number of people in our grass-roots effort."
The Columbia native, who moved to the island in 1999, said his campaign was closely targeted to people likely to vote in the Republican primary based on voting trends in the 2002 gubernatorial election.
Supporters made phone calls and organized get-togethers for Chalk, he said, and he sent direct-mail fliers to likely voters near the end of the campaign.
"Over the weekend we just did last-minute phone calls to encourage them to come out and vote," he said.
Chalk, a commercial real estate agent, ran largely on his past experience as a state lawmaker. His top issues included improving public education, lowering the amount of punitive damages allowed in tort claims, and protecting natural resources.
Hairston, a former flight attendant, ran on her record of community involvement and focused on improving public education, expanding economic development and reforming the state's tax structure.
Her campaign included television and radio commercials, she said, aired just a few days before the election. She also operated a phone bank, sent out direct-mail fliers and went door-to-door handing out leaflets.
Both candidates talked about their positions, many of which were similar, at local club meetings, forums and debates on the island.
They spent most of Tuesday shaking hands outside the Plantation House at Hilton Head Plantation, where four island precincts were voting.
"I think that we ran a good race," Hairston said Tuesday night from her home, after calling Chalk to congratulate him. "I did everything I feel like I could do.
"I'm ready to continue to work for my constituents in (County Council) District 2."
Hairston is serving her first term on the County Council. She was elected in 2002.
Both Hairston and Chalk said they would work to make sure other Republican candidates are elected in November.
Chalk said he did not expect to do much more campaigning before November unless a petition candidate files. But he will become more involved with community organizations on the island.
"Just the things you need to do as an elected official to be in touch with your constituency," he said.
In other Lowcountry races:
State Rep. Walter Lloyd of Walterboro won the Democratic primary for the District 121 seat, with 82 percent of the vote compared to James D. Adams' 18 percent, according to unofficial results.
In early reports from District 122, state Rep. Thayer Rivers Jr. of Ridgeland was beating challenger Curtis Brantley 54 percent to 46 percent. Twenty-two of 31 precincts had reported at press time.
There was no Republican Party opposition to either House seat.