Miller will join Hull FC in the English Super League on a two-and-a-half year deal once his visa is cleared.
Last season, Miller captained the Wests Tigers to their inaugural NYC premiership. He played nine NRL games for Wests Tigers.
"I am obviously leaving a club that I have close ties with and I have some good friends here,'' Miller said.
"I would like to thank the Club, the coaches, the players and the fans for their support over the last few years and wish them all the very best for the future and hopefully a strong run for the rest of the season."
Wests Tigers wish Jacob all the best for the future.