Gujarat Congress leader Hardik Patel, who was in Morbi district on Friday to attend a case hearing, was arrested by Ahmedabad police from outside the court.
He was held in a three-year-old case of rioting lodged at Ramol police station, said officials.
Mr Hardik was arrested by Ramol police as soon as he came out of a magistrate's court in Tankara town in Morbi district.
"We have arrested Hardik Patel from outside a court in Tankara after a non-bailable warrant was issued against him by a court in Ahmedabad in a rioting case lodged in March 2017. The FIR was lodged by BJP corporator Paresh Patel, who had accused Hardik and others of trespassing and rioting at his residence," said Inspector KS Dave.
The FIR was lodged at a time when Hardik was leading an agitation demanding OBC reservations for Patidars.
In all, some 25 cases have been lodged against Hardik in different parts of the state, mostly for holding rallies without police permission. He is also facing two sedition FIRs at Ahmedabad and Surat.