David Martindale has been appointed Livingston manager until the end of the season after winning all four games in caretaker charge.
Martindale also guided Livingston into the Betfred Cup semi-finals after Gary Holt's resignation and has previously been assistant manager and the club's head of football operations.
He joined the club's coaching staff in 2014 having being sentenced to six-and-a-half years in prison in 2006 for organised crime offences.
In a statement, Martindale said: "I can honestly say I owe a huge gratitude to Livingston FC, the fans, the players, and all the directors over the years as they have given me the opportunity to work in professional football and allowed me the chance to progress my own career while changing mine and my family's life.
"Without having such open-minded people throughout my time at Livingston, there is no doubt I wouldn't be in this position today.
"I spent a large part of my life growing up in Livingston and I can honestly say I will do everything in my power to continue to push, pull and cajole Livingston FC to keep on punching above our weight.
"I owe the fans of this club a massive thank you as they have been magnificent in my time here already and I won't forget that.
"I will strive every day to make this club a club you can all be proud of - both on and off the park."
Livingston sit seventh in the Scottish Premiership and will also face St Mirren next month for a place in the Scottish League Cup final.
Martindale's first game in permanent charge will be a trip to Hamilton on Wednesday, before a visit to Kilmarnock on Boxing Day.
He previously declined the role in 2018 because he felt it was not the right time, but chairman Robert Wilson is delighted he has taken on the post this time around.
"The level of work that David has put in since arriving at the club in 2014 has been phenomenal and he thoroughly deserves this appointment," Wilson added.
"There has been nobody at this football club who has worked harder than he has over the past six years and the club has went from strength to strength since his arrival."