Ferrer will square off in Sunday's championship match against No. 2 seed Stanislas Wawrinka of Switzerland, who needed three sets to top Spanish qualifier Pablo Carreno-Busta.
Ferrer needed 68 minutes to get past Seppi. He converted four of eight break-point chances to reach his fifth finals of the year.
Wawrinka scored 10 aces against Carreno-Busta and broke serve three times.