Ferrer had led 5-2 in the first set overnight when the semi-final was suspended due to violent storms which battered New York, but Djokovic thrived under clear blue skies on Sunday, allowing the Spaniard just eight more games.
Splendid win: Djokovic celebrates
The victory gave the second-seeded Serb a year-leading 60th win and extended his winning run at hardcourt Grand Slams to 27 matches.
Djokovic will be aiming for a sixth major in Monday's final while third-seed Murray, who trails the Serb 8-6 in career meetings, is bidding to become Britain's first men's Grand Slam champion since Fred Perry in 1936. Victory by the Serb in the championship match would mean 30 out of the last 31 majors have been won by either Djokovic, Roger Federer or Rafael Nadal.