In this week's episode, 'Asian F', Mike's parents appear and he performs the West Side Story song 'Cool'.
"What I loved about the number is that it is so raw," Shum told TV Guide. "The turns, the way they land... but also, the emotion in the number."
Shum added that he expects a lot more to happen to Mike in the future.
"From what I've seen, I've got a story that will continue through senior year," he said. "You'll see Mike's parents again, for sure.
"Ryan [Murphy], Brad [Falchuk], Ian [Brennan] and the other writers I think are holding true to what they've said about bringing other characters into the spotlight and discovering more things about them. It may take a while but they're slowly taking care of the other characters. I'm really glad they're doing it."
Shum also revealed that none of the cast members are really thinking about the prospect of graduation later this season.
"Everyone's happy with the way the stories have been written," he said. "It's coming up very slowly but I think they've been doing it in a way where you're following along and you're happy to be following along. It's not about looking so far ahead into the results - it's more about the journey."
Shum has previously teased that Glee will be "diving deeper" into Mike's life and hinted that the introduction of his parents will give more information about his home life.
Glee airs on Tuesdays at 8/7c on Fox in the US and on Thursdays at 9pm on Sky1 in the UK.
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