Billingsley (12-11) was sharp, yielding two runs on four hits over 7 1/3 innings, walking only one to go with his nine strikeouts.
Ramon Trancoso worked out of an eighth-inning jam and Kenley Jansen picked up his fourth save in the ninth for the Dodgers, who evened their season-ending, three-game series with the Diamondbacks.
Kemp's fifth-inning blast put the Dodgers up 2-0 and Reed Johnson added a sacrifice fly in the sixth.
Arizona starter Joe Saunders (3-7) allowed three runs on 10 hits in seven frames.
Steven Drew and Tony Abreu drove in runs for the D-backs.