While mainstream critics were divided about Todd Haynes' take on the many facets of Bob Dylan, most agreed that Cate Blanchett was the best thing about "I'm Not There." Though the film scored 80 based on 59 reviews compiled by Rotten Tomatoes, it managed only 67 from the Cream of the Crop. This lower number is also reflected in the score of 74 calculated by Meta Critic from the opinions of 21 leading critics.

As Jack Mathews of the New York Daily News observes, "No movie this season is likely to polarize critics and audiences more. Some of it is brilliant, some is tedious and some is just plain incoherent. As to the mosaic that eventually comes into focus, all I can say is that if Dylan signed off on this, the times they indeed are a-changin'. He has always had a higher opinion of himself." He adds, "Most of the early talk about 'I'm Not There' has focused on the performance of Blanchett, who proved herself a deft impersonator as Katharine Hepburn in 'The Aviator.' Here, with her hair curled and her bosom flattened against her tiny frame, she looks and sounds more like Dylan than any of the others."

Writing in Maxim, Pete Hammond says, "Todd Haynes comes up with the most unique and astonishing idea for a musical biography in light-years, casting six different actors (including one woman) as distinct variations on the legendary Bob Dylan. Heath Ledger, Richard Gere, Christian Bale, Marcus Carl Franklin, Ben Whishaw, and, yes, Cate Blanchett all play Dylan at key points in his life. And though the results are uneven in this overlong (135 minutes) dissertation of all things Dylan, when it works it soars." Pete thought, "Through sheer skill and brilliance she (Blanchett) has delivered the most audacious, astounding, and entertaining performance of the year by anyone, male or female."