Under Cook Spireites bagged the League Two title in 2013/14 before play-off semi-final disappointment followed in League One the season after with defeat at Preston.
He joined Chesterfield after success with Accrington on 25th October 2012 following the departure of John Sheridan.
The end of his first season saw Cook guide Chesterfield to eighth position, finishing just two points outside the play-off zone before two successful seasons followed.
The in-demand manager eventually left for Portsmouth in May 2015, where he won the League Two title once again the following season.
Here we look at just some of the memories from his first spell at Chesterfield.
1. Paul Cook takes charge
Paul Cook is pictured after being unveiled as the new Chesterfield manager on 26th October 2012. It began a spell of attacking football and success at the club. Photo: Terry Walden
2. Goal celebrations
Paul Cook celebrates a Chesterfield goal in a 2-0 win over AFC Wimbledon in February 2013. Goals would be a common theme for Spireites, who scored 60 goals that season, before finishing the following year as the division's top scorers. Photo: Marisa Cashill
3. Lester's last match
Manager Paul Cook greets Jack Lester off the pitch one final time in a home game against Exeter City. Photo: Tina Jenner
4. Wembley place is booked - 2014
Although Chesterfield were beaten 1-0 on the night it was enough to secure their place at Wembley for the JPT Trophy final with a 3-2 win on aggregate. Photo: Tony Marshall