Marianne Williamson, the self-help author now on her second long-shot run for president, appeared to finish ahead of Representative Dean Phillips of Minnesota in the South Carolina Democratic primary on Saturday, inching past the candidate who has so far been President Biden’s most significant, albeit distant, rival.

With 97 percent of votes counted, Ms. Williamson has 2.1 percent and Mr. Phillips has 1.7 percent. While the race is an overwhelming victory for Mr. Biden — with more than 96 percent — it is nonetheless the most support Ms. Williamson has received in an official Democratic primary. She ended her 2020 campaign weeks before the Iowa caucuses.

Ms. Williamson’s very distant second-place finish is a significant blow to Mr. Phillips. His campaign spent about $4.6 million in the last three months of 2023, and he lent it $4 million of his own money, according to a filing with the Federal Election Commission.

Mr. Phillips had tried to set very low expectations for his performance in South Carolina. He projected on social media on Friday that Mr. Biden “should get 95 percent of the vote in South Carolina.” His forecast was not far off.

Mr. Phillips appeared to take his third-place finish on Saturday in stride. “Cracking four digits never felt so good!” he wrote on social media, referring to the roughly 1,400 votes he had at the time. (He finished with some 2,200.) He added: “Congratulations, Mr. President, on a good old fashioned whooping. See you in Michigan.”

Both of Mr. Biden’s challengers appeared infrequently at campaign events in South Carolina, though Ms. Williamson began visiting the state nearly a year ago, and Mr. Phillips made his first trip after joining the race in November.

The Post and Courier reported that at one event last month in Columbia, S.C., staff members with Mr. Phillips’s campaign feared attendance would not be high enough to justify the number of chairs they had set up. They arranged a smaller number in a circle for the 10 people who ultimately showed up. “This feels like a séance,” Mr. Phillips said when he walked into the room.

He put significantly more effort into campaigning in New Hampshire, where he hoped for an upset performance that would have given him momentum in the race. He finished with less than 20 percent of the vote, losing overwhelmingly to Mr. Biden, who was not, in fact, on the ballot.

Still, he beat Ms. Williamson by more than 15 points.