McLeish had been out of work since being dismissed by Aston Villa in May but is viewed by Forest's Kuwaiti owners as the manager to guide the east midlands club to the Barclays Premier League. The 53-year-old Scot welcomed the opportunity to join a club lying eighth in the Championship, just a point outside the play-offs.
He replaced the sacked Sean O'Driscoll and told club website nottinghamforest.co.uk: "I'm really looking forward to working with Nottingham Forest. I've had time away from the game and now feel refreshed and ready to go."
He continued: "The fact that a club of Forest's magnitude has offered me a job excites me greatly - it's a wonderful opportunity. I can't wait to get started and I'm looking forward to meeting the players, talking to them and taking my first training session."
McLeish was confirmed in the Forest hotseat on Thursday evening - a day after the club raised eyebrows with their decision to dismiss O'Driscoll, who hours earlier had overseen a 4-2 win over Leeds.
Forest chairman Fawaz Al Hasawi revealed that the club were keen to appoint a manager with Premier League experience, something McLeish gleaned during stints at Birmingham and Villa.
"I'm delighted to welcome Alex to our club and look forward to working with him," Al Hasawi said. "Alex took Birmingham to promotion from the Championship and has great experience of working in the Premier League. He's hungry for more success and I believe he's the man who can help us fulfil our ambition of making it to the Premier League."
After a successful career north of the border that took in spells in charge of Motherwell, Hibernian, Rangers and the Scotland national team, McLeish moved to English football in November 2007, joining a Birmingham side battling relegation from the Premier League.
Although he failed to save the club from the drop, he guided Blues back to the Premier League the following season and went on to secure a ninth-placed finish at the end of the 2009-10 campaign.
A shock victory over Arsenal in the Carling Cup final followed in February 2011, but that was followed by an alarming slump that saw Birmingham relegated at the end of the season. McLeish left Birmingham amid acrimony to take charge of Villa, but lasted just one season at the helm, avoiding relegation by just two points and failing to win over the club's fans.
Source: PA
Source: PA