Former Birmingham boss McLeish has upset some sections of Villa supporters by making the move across the city to replace Houllier.
But Houllier, who was forced to quit because of health reasons three weeks ago, believes McLeish should be given the opportunity to show his credentials.
He said: "I think Gabby Agbonlahor (Villa striker) said some comments about giving him (McLeish) a chance - and I agree.
"He's football through and through and I think he's a good signing for the club.
"I've known him a long time and he's a nice person and a straightforward guy.