The former Blue Brazil skipper moved to Saints last summer but struggled to get to grips with life in the top-flight as he made just 12 starts, and he returned to Cowdenbeath's Central Park on loan in February.
After just one substitute appearance for Danny Lennon's St Mirren side this term, he has been allowed to join his old club again on a permanent deal.
A spokesman for St Mirren said: "We would like to wish Jon - who leaves Saints having made 22 appearances for the club - all the best for the future."
- Danny Lennon
- St Mirren