"I didn't necessarily know that it was going to be our last season next year," he tells Access Hollywood a few days after show creator Ryan Murphy first revealed to The Hollywood Reporter that Colfer, Lea Michele and Cory Monteith would graduate after the next season.
"I knew something like that was coming up eventually. I mean, we can't be there forever," adds Colfer, who earned an Emmy nomination Thursday for playing Kurt Hummel. He also won a Golden Globe for the role earlier this year.
Still, that doesn't mean he's eager to depart the Fox hit. "Do I want to leave the show? Absolutely not," he tells Extra. "This is home for me. But I understand that there's time for a conclusion."
Colfer next stars in the indie coming-of-age comedy "Struck by Lightning," which he also wrote. It hits big screens next year. Allison Janney co-stars as his mom.
Colfer also sold a pilot to Disney Channel titled "The Little Leftover Witch," based on Florence Laughlin's children's book, which tells the tale of a witch who is taken in by a new family after her broom breaks and she drops out of the sky.
In addition, he has a two-book deal with Little, Brown Books for young readers. "The Land of Stories," due in summer 2012, will tell the story of twins Alex and Connor Bailey and be a fast-paced adventure series that combines the modern world with fairytales. It will target readers ages 8-12 and be followed by a second novel that is yet to be titled.
He will appear along with the rest of the cast in "Glee: The 3D Concert Movie," which opens Aug. 12.
(Additional editing by Jillian Mapes, Billboard)