He will also take on the director of rugby role vacated by Jonno Gibbes.
Ronan O'Gara has put pen to paper on a new three-year contract with La Rochelle.
The former Ireland and Munster out-half says he's "extremely proud" to be remaining as the Top 14 high flyer's head-coach.
O'Gara has thanked the club's owners for showing confidence in him as they continue to prepare for a European semi-final showdown with Leinster.
La Rochelle have also confirmed that former Leinster and Ulster coach Jonno Gibbes will leave them to become Clermont's new head-coach this summer.
Statement in full from La Rochelle:
Discussions were initiated a few weeks ago at Jono Gibbes’ request which lead to his early release from June 30. At the same time, Stade Rochelais has worked to preserve both ambition and stability of its project.
The Club’s priority was to extend its collaboration with its head coach, Ronan O’Gara, and promote him at the head of the professional team.
The Club is therefore delighted with Ronan’s re-engagement until 2024 and his loyalty to the Stade Rochelais’ project, which he will continue to strengthen through his managerial skills, his top level experience and his full immersion in the club culture.
Head coach of Stade Rochelais since July 2019, the Irish tactician with 128 selections began his coaching career at Racing 92 in 2013 (French Champion 2016), before joining the Crusaders in 2018.
Speaking on the announcement, Ronan O'Gara said:
I am extremely proud of the trust that Stade Rochelais continues to show me by appointing me at the head of the team. I am obviously very excited about next season, but first, we have important challenges ahead of us and above all a good season to end in the best possible way.
Stade Rochelais would like to thank Jono for his contribution to the performances of the Yellow and Black team since his arrival in 2018 and wish him the best for the rest of his professional career.