The 25-year-old Barty, who won her maiden Grand Slam at Roland Garros in 2019, emulated her idol Evonne Goolagong who claimed the second of her All England Club titles in 1980.
"I hope I made Evonne proud," Barty said on court after the trophy presentation. "This is incredible."
Ten years after winning the girls' singles title at Wimbledon as a 15-year-old, Barty came into the final having won five of the seven matches she had played against Pliskova.
She breezed to a 4-0 lead against the former world number one with a double break.