He struggled to win over a sceptical fan base throughout his two years in the North West, having initially joined the club in October 2007.
A poor opening to the 2009/10 campaign ultimately sealed his fate, with the Bolton fans getting the change in direction they had been calling for.
Not everyone connected with the club is pleased to see Megson gone, though, with highly-rated centre-half Cahill admitting he will be forever grateful to the former Norwich and Nottingham Forest chief.
The 24-year-old was stuck in Aston Villa's reserves when Bolton came calling in January 2008, but he has blossomed into one of the Premier League's most commanding defenders since then and finds himself on the fringes of Fabio Capello's England plans with the World Cup fast approaching.
"I appreciate everything he has done for me," Cahill said on the impact Megson made on his career.
"If you look at where I have come from since I first joined the club, here I am now and I am probably the fifth-choice centre-back for England, with still years in front of me.
"I am definitely a better player than when I first came here. I played a lot under him, and he took a chance and paid a lot of money for me at that stage of my career.
"I would like to think I have repaid him in a way, but I am grateful for what he did for me."
Cahill is also of the opinion that whoever takes the vacant Bolton post will be inheriting a talented bunch of players, but admits anyone keen on the role may decide to wait until after Wednesday's daunting trip to Arsenal before taking the reins.
"Whoever comes in will inherit a good bunch of players and they are going to come into a very good club," he added.
"Every name under the sun is being touted about, but I imagine whoever it is won't be sprinting to get to Arsenal - that's just true. We will probably have to go there in the situation we are in now."
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