President-elect Donald J. Trump has called the American economy a “disaster.” But in Sioux Falls, S.D., Scott Lawrence, a local businessman and Trump voter, has a different take.

“Businesses that were hunkered down earlier in the year have come on strong,” said Mr. Lawrence, who runs a local advertising firm, Lawrence & Schiller, which employs 95 people. “I’m definitely more optimistic than I was six months ago.”

Mr. Lawrence is putting his money where his mouth is: His company hired five employees late last year, including digital strategists and content designers, and he plans to add another four in the next three months.

Although Mr. Trump was able to capture the White House by portraying an American economy in shambles, many of the economic fundamentals are solid.