The decision comes after the former Wallaby and RA failed to reach an agreement at a mediation hearing at the Fair Work Commission on June 28.
"Unfortunately, our conciliation before the Fair Work Commission did not resolve the matters between us and I have been left with no choice but to commence court action," Folau said in a statement on Thursday.
RA terminated Folau's multimillion dollar contract over a social media post in which he paraphrased a Bible passage, saying "drunks, homosexuals, adulterers, liars, fornicators, thieves, atheists and idolaters" would go to hell unless they repented.
The committed Christian argues he was unfairly dismissed on religious grounds.
Folau, 30, is seeking $10 million in damages from RA and wants his contract reinstated.
More than 20,000 people have donated about $2.2 million to help fund Folau's legal battle via a campaign page set up by the Australian Christian Lobby.
The ACL effort replaced an earlier campaign on GoFundMe, which was taken down by the platform for breaching its service guidelines.
Folau thanked his many supporters in the statement.
"I have been blessed to have received the support of tens of thousands of Australians throughout my journey, and I want to say thank you to everyone who has offered their prayers and support. It has meant so much to (wife) Maria and me over the last few months and gives us strength for the road ahead," he said.