However, an increase in costs also saw its net loss grow to $138.8m (£99.5m/€116.0m).
Total revenue for the 12 months to December 31, 2020 amounted to $278.5m, up from $63.7m in the previous year.
RSI did not publish a full breakdown of revenue, but noted its online casino operations outperformed sports betting by three-to-one in both New Jersey and Pennsylvania in 2020.
Online casino, which includes slots and tables but excludes poker, accounted for 76.7% of revenue in Pennsylvania last year, compared to 23.3% for sports betting, while casino was responsible for 72.1% of New Jersey, ahead of sports betting on 27.9%.
However, full-year operating costs and expenses rocketed by 379% year-on-year to $411.9m, with the cost of revenue being RSI’s main outgoing, jumping 480% to $190.9m.