Biden won 48.7% of the popular vote and notably placed first in every county in the state; it was his first ever win in a presidential primary.

Businessman Tom Steyer, who had staked his entire campaign on the state, placed third but did not surpass the threshold and dropped out of the race, endorsing Biden.

Following successes in the previous primaries, former mayor Pete Buttigieg and senator Amy Klobuchar received very disappointing results and initially wanted to stay in the race, but they both suspended their campaigns shortly before Super Tuesday and endorsed Biden on the day before.

In the open primary, candidates had to meet a viability threshold of 15 percent at the congressional district or statewide level in order to be considered viable.

[5] Voting was done by each voter selecting choices on a screen, so the machine printed a ballot with chosen names and a bar code.

[16] Official results show that Joe Biden won the Democratic primary with 48.65% of the vote, with Bernie Sanders coming in second with 19.77%.

[76][77] Joe Biden's overwhelming victory, his first-ever primary win in his three presidential runs,[78][79] gave his campaign new momentum going into Super Tuesday after lackluster performances in Iowa and New Hampshire and a distant second-place finish in Nevada.

Steyer's campaign had concentrated its advertising efforts on South Carolina, spending more money on television commercials in the state than all the other Democratic candidates combined.

[1] On February 28, 2020, former Governor of Virginia Terry McAuliffe stated that he would consider endorsing Biden if he performed well in the South Carolina primary.

[94] Before the primary on February 26, House Majority Whip and longtime U.S. Representative Jim Clyburn endorsed Biden.

[96] Thirty-six percent of all primary voters said that they made their decision after Clyburn's endorsement; of that total, 70% voted for Biden.

[98] Following the South Carolina primary, pollsters and analysts claimed that Buttigieg, Warren, and Klobuchar were losing momentum at a critical time in the race.

[101] Following their poor performances, Pete Buttigieg,[102] Amy Klobuchar,[103] and Tom Steyer[1] ended their presidential campaigns before Super Tuesday.