Jackson told a rally in Columbia that the Democrat would fight for jobs, education and health care for all Americans, not just the wealthy. South Carolina holds its primary Feb. 3.
Dean was also endorsed Sunday by Rep. Robert C. Scott, D-Va. Scott is the only black in the congressional delegation from Virginia, which holds its primary Feb. 10.
Sharpton cited 1995 comments by Dean in which he said, "I think we ought to look at affirmative action programs based not on race but on class and opportunities to participate."
Dean has since said he thinks affirmative action has to be about race.
Jackson's father, Jesse Jackson Sr., who ran for the Democratic presidential nomination himself in 1984 and 1988, has endorsed none of the nine candidates in the 2004 campaign. Spokeswoman Keiana Barrett said for now the elder Jackson is "channeling his energies behind defining the ideal platform" for the Democratic Party.