The CW drama's fourth run, which will follow its characters to college, will begin next month.
Steger told The TV Addict: "I keep saying [it will last] five years. But you know, that always changes. The CW likes to hold on to its shows."
The actor, who plays Navid Shirazi, nevertheless insisted that 90210 will "end soon".
"I realise [that this series is] going to be a great platform to get other jobs... when the show's over," he said. "Because let's face it, it's going to end soon, or one of these days."
Steger added: "I'd love to do other films and hopefully the show will allow me to do that."
Ryan Rottman, Sean Wing, Sarah Hagan, Matt Cohen, Justin Deeley, Megalyn Echikunwoke and Kristina Apgar have all signed up for roles on 90210.
The show's new season begins on September 13 on The CW.
> American Idol's Kellie Pickler to star on 90210
Watch a clip from the 90210 third season finale below: