The Irishman has rejoined the club he captained for five years, signing a three-year deal.
The 37-year-old replaces Oran Kearney, pictured inset, who was axed following a row with chairman Gordon Scott over his plans to commute daily from his family home in Northern Ireland.
Goodwin, who skippered Saints to their first trophy in 26 years when he lifted the League Cup in 2013, insists he will not take the opportunity ahead of him for granted after being given the green light by Alloa Athletic to move back to Renfrewshire.
Goodwin will officially start work on Monday when he meets his new squad for the first time as they jet out to Spain for a pre-season camp.
Youth coaches Allan McManus and Andy Webster were in charge of the team for last night’s friendly clash with Belfast amateurs Rosario Juniors.
Goodwin said: “I am absolutely delighted to have been offered the job as manager of this great club.
“I had three wonderful seasons at Alloa and loved every minute of it, but the opportunity to come back to the place where I had my most memorable spell as a player was too good to turn down.
“This is a very proud moment for me and one I will never take for granted. I’m looking forward to meeting the staff and players next week, and genuinely can’t wait to get started.”
Goodwin, who will be assisted by his Wasps number two and former Saints defender Lee Sharp, racked up more than 180 appearances for the Paisley club after signing from Hamilton in 2011.
Two years later he became just the fourth St Mirren captain to get his hands on a major piece of silverware as Danny Lennon’s team beat Hearts 3-2 in the League Cup final at Hampden, and his achievements as a player saw him inducted into Saints’ Hall of Fame in October 2017 as part of the club’s 140th Anniversary celebrations.
He joined Alloa after being released in the summer of 2016 and stepped up to replace Jack Ross as boss at Recreation Park three months later when his old Saints team-mate was lured back to Paisley himself.
Goodwin led the Wasps to promotion from Ladbrokes League One the following season and then guided them to Championship survival last year despite being the only part-time team in the division.
Now Scott hopes his new manager can reproduce those kind of results with St Mirren.
The chairman said: “I am absolutely delighted to welcome Jim back to St Mirren.
“He was a firm fans’ favourite as a player here and I know he will receive terrific backing from our support as our new manager.
“I would like to thank Alloa Athletic for their co-operation in allowing us the opportunity to speak with Jim.”
Wasps owner Mike Mulraney said: “Obviously the Alloa fans will be disappointed that we have lost another manger, but we are sure you will agree with the board that both go with our gratitude for the outstanding service they have given Alloa Athletic.
“We are sure they will be a success in the future and we wish them well.
“Special mention must go to Jim who has had an outstanding tenure as Alloa manager and has given everything to the club in his time here.
“His effort has been reflected in the results the team have achieved. We would also like to record that St Mirren have conducted the process impeccably at all times.”