"I knew I had to start very strong today and continue that throughout the game," the 28-year-old said after recording her 30th Fed Cup victory.
"From the beginning of the match I knew I had all the weapons."
Earlier in the day, German number one Julia Goerges had dragged her country back into the tie with a 6-4 6-2 win over Karolina Pliskova.
Goerges needed only 27 minutes to claim the opening set before she took advantage of the first two break opportunities in the second to clinch the victory in under an hour.
But former world number one Kerber struggled to cope with Kvitova's powerful groundstrokes and was broken five times as the Czechs returned to the final after a one-year absence.
Barbora Strycova and Katerina Siniakova clinched the doubles dead rubber after Goerges, paired with Anna-Lena Groenefeld, retired injured at the end of the first set, which the Germans lost 7-5.
The Czechs are undefeated in their previous five final appearances and will face either France or the U.S. in the final on Nov. 10-11.
(Reporting by Hardik Vyas in Bengaluru; editing by Clare Fallon)
