Potter led the Dragons to last year's Challenge Cup final
Catalans Dragons coach Mick Potter will succeed Daniel Anderson at the helm of St Helens at the end of the season.
"Mick is a first-class coach and is improving year in year out," said Saints chief executive Tony Colquitt.
"He is exactly what we will need next season to take over a pretty difficult mantle in replacing Daniel."
Australian Potter, who has agreed a two-year deal, said it was an "honour" and "privilege" to be appointed coach of "this world famous club".
Anderson, who steered Saints to the treble in 2006, will end his reign at the end of the season in order to return home to Australia.
He brings the energy, enthusiasm and toughness he had as a player
Saints chief executive
Potter will continue as Catalans coach for the rest of 2008.
The 44-year-old emerged as favourite to succeed Anderson after guiding the Dragons to last year's Challenge Cup final at Wembley.
They lost to Saints that day but have continued to improve under Potter, climbing to third place in the Super League table.
The French club had offered Potter a new two-year deal but he turned that down to accept the challenge at Knowsley Road.
Potter, a full-back with National Rugby League clubs Canterbury Bulldogs, St George and Perth Western Reds, cut his coaching teeth as an assistant to Matthew Elliot at Bradford Bulls from 1996-1998.
He joined the backroom staff of St George on his return to Australia and coached the New South Wales Under-17 squad before being head-hunted by former Great Britain coach David Waite to take on at the Dragons in February 2006.
Potter said: "I am looking forward to next season. However, my immediate commitment is to the Catalan Dragons, its players and supporters as we look to continue the good work and progression the club has achieved."
Colquitt told BBC 5 Live: "He was an all-time great in Australia, he was a great full-back.
"He brings the energy, enthusiasm and toughness he had as a player. He certainly understands players and how they play.
"We are really excited but that is for next season. This season we are focused on Daniel and the team and I am sure Mike will be focussing on the Catalans on their team and we will talk about it in October and November."