Annette Echikunwoke of the United States took a surprise silver with 75.48 and China's Zhao Jie won bronze (74.27).
Rogers, 25, added the Olympic crown to the world title she won last year in Budapest, her victory at Stade de France coming two days after teammate Ethan Katzberg claimed the men's gold.
Echikunwoke arrived in Paris with the world's ninth best throw this season but briefly led before Rogers coolly stepped into the circle to reclaim the lead in the fifth of six rounds.
The Canadian already had victory locked up before her final throw, but did not break into a smile until the 4kg hammer had left her hands. She then made a beeline for her mum Shari Rogers, a fixture at all her daughter's competitions.
Rogers was fifth on her Olympic debut in Tokyo, then took world silver in 2022 before victory last year in Budapest.
Wlodarczyk, the world record holder with a staggering 82.98, was fourth on 74.23.
