The Egyptian striker is trying to resurrect his career in Europe after disappointing loan spells at English Premier League duo Wigan Athletic and West Ham United.
He joined Ajax, the club where he made his name in the early 2000s, from English second-division side Middlesbrough on a season-long loan.
He took part in his first training session with the Dutch giants on Wednesday after gaining the work permit.
"I'm glad to be back," Mido, who looked over-weight in the pictures posted on the club's official website, told Ajax TV.
"I couldn't speak with everyone today but I met (former teammates) Thimothee Atouba and Mounir El Hamdaoui, whom I know from my time at Tottenham Hotspur."
The 27-year-old enjoyed a successful spell at Tottenham between 2005 and 2007 when he was coached by Jol.
Both men are reunited again to the delight of Mido, who was full of praise for the Dutchman.
"I have a good relationship with Jol. He is honest and a real leader and he knows how to get the best out of me."
The much-traveled striker said recently he hoped to play against Spanish giants Real Madrid in the European Champions League Group G clash on September 15.
However, he seems unlikely to make Ajax's squad for the anticipated game.
"I think I need two to three weeks to return to action," Mido, who spent the first half of last season at his boyhood club Zamalek, added.