The former wrestler reportedly earned $87.5m (£67m) between 1 June 2019 and 1 June 2020, including $23.5m for the Netflix thriller Red Notice.
He also made money from his fitness clothing line, Project Rock.
The 10 top earners combined made $545.5m this year - more than a quarter of that from Netflix, Forbes said.
Johnson's Red Notice co-star Ryan Reynolds was the second-highest paid actor, with earnings of $71.5m. Among his movie deals were $20m, also for Red Notice, and $20m for Six Underground, another Netflix film.