The tune is a ballad instead of a shuffle, but Rucker is thrilled nonetheless.
"We expected some success, but this is unbelievable," he said Thursday from his home in Charleston, S.C.
His country CD, "Learn to Live," comes out Sept. 16.
Rucker, who said Hootie is on hiatus but will be back, has been talking about making a country record for a while. He was ready to do one in Charleston when Capitol Nashville expressed interest in the project.
"It shocked me. I didn't think anybody had a desire to sign Darius Rucker," he said.
In some ways, the 42-year-old Rucker says, he's been making country music all along. Foster & Lloyd and Dwight Yoakam were big influences on his songwriting.
"Back in the day I wrote a lot of country songs and we turned them into rock and roll songs. Now I get to write those songs and play them as country," he said.
"If this record was 12 shuffles and a ballad, I'd be real happy," he added.
His timing is good for crossing over. Country radio seems wide-open with Jewel, the Eagles and Bon Jovi all finding success. Besides Rucker, this week's Billboard country Top 10 also includes Kid Rock's "All Summer Long."
"Pop is so beat-oriented," Rucker said. "Country is where you can still get that song that makes you remember that old girlfriend or whatever. Country still has a story to it."
With "Don't Think I Don't Think About It," Rucker becomes the first black to crack the country Top 10 since Charley Pride in the late '80s.
Rucker said he doesn't think about that.
"I was just trying to make a record that people wanted to hear," he said.