Barman Karl, married to Stella (Michelle Collins), won £1,000 from Ciaran McCarthy (Keith Duffy) in a game of poker earlier this week.
However, ex-Taggart star Michie has teased details of his alter ego's descent into debt after "a few big losses".
He told the Daily Record: "He is going to be gambling for a while and eventually he will have a few big losses, which is great for me.
"You know what gamblers are like, he has to lie, drinks a little bit more than he should and it is going to cause tension in his relationships."
The 55-year-old explained that his involvement in Corrie will increase in 2012 as a result of the plot.
"This is Karl getting his feet under the table, in a sense," he continued. "When I was asked to join the show, I was told initially they would bed me in and there is a lot planned for next year. He needs a strong storyline like this for people to get inside his mind a bit.
"I've really worked out who Karl is. It's just the audience who have to get to know him and that's happening about now."