The 54-year-old journalist - who has reportedly been approached by rival networks ABC, CNN and NBC - revealed she stepped down from the position she held for five years in favour of doing a job that will enable her to take on "more multi-dimensional storytelling".
She said: "The bottom line is that I love doing all kinds of different stories. I have a lot of areas of interest and I want to be able to fulfill all of that.
"I am looking at a format that will allow me to engage in more multi-dimensional storytelling."
There had been plenty of speculation about whether Katie - who once made a guest appearance on 'Glee', playing herself - would remain at the network, but she is now focused on the next step of her career.
She added to People magazine: "In making the decision to move on, I know the 'Evening News' will be in great hands, but I am excited about the future.
"I'm really proud of the talented team on the CBS 'Evening News' and the award-winning work we've been able to do in the past five years in addition to the reporting I've done for '60 Minutes' and 'CBS Sunday Morning'."