The BBC Radio 1Xtra presenter will replace Caroline Flack, who announced her decision to leave the ITV2 spinoff yesterday (June 11) after three years, and comedian Matt Richardson.
Taking to Twitter, Crawford said that she was "really thrilled" to have been chosen by Simon Cowell and fellow show bosses.
Morning! Really thrilled to say that I'll be the new host of #XtraFactor this year!!!! Thanks to the X team for seeing something in me! ❤️— Sarah-Jane Crawford (@DJSarahJane) June 12, 2014
"Massive respect goes out to @carolineflack1 who's an amazing broadcaster and delivered 3 years of a brilliant series," she added.
Elsewhere, Crawford said that she has watched every series of The X Factor "religiously", adding: "To be the new host of The Xtra Factor in its most exciting year ever is what dreams are made of.
"I'll be asking the judges the questions that people at home are screaming at their TVs - and you'd better believe I'm going in with a bang! I just can't wait to get on the road now and meet the auditionees!"
The Xtra Factor's executive producer Mark Sidaway described Crawford as a "great addition to the team", praising her "fantastic knowledge of the music scene", her "great sense of humour", and her interview experience.
Host Dermot O'Leary also congratulated Crawford on her appointment, tweeting: "Sad to see my little sis @carolineflack1 go. But welcome to the family @DJSarahJane ... The strange dysfunctional family."
Meanwhile, Flack's former co-host Richardson - who joined the series last year - has also announced that he will not return for the upcoming run.
Major Congrats to @DJSarahJane on xtra, I shall remember it well whilst writing my new tour. Advice: Judges Houses is not a holiday (it is)!— Matt Richardson (@MattRichardson3) June 12, 2014
It was confirmed yesterday that Mel B will be this year's fourth X Factor judge alongside Cowell, Cheryl Cole and Louis Walsh.