He called Obama the "right leader for our times."
Crist could be one of several Republicans included at the Democratic convention, in an effort to prove Obama is willing to reach across the aisle. Crist, who was defeated by Marco Rubio (R) in Florida's 2009 Senate race, has been criticized by conservatives for getting too friendly with Democrats. He switched his party affiliation to Independent in 2009.
The Democratic convention begins next Tuesday in Charlotte, N.C. The scheduled time of Crist's speech has not yet been released.