Michelle as Harriet creates one of the greatest child characters for pre-teen audiences. What this movie lacks in visual polish, it more than makes up in showing the world through eyes of an inquisitive, a tad hyperactive sixth grader. Adults in Harriet's world are just what they should be from the point of view of a self-confident, headstrong tomboy: a mixture of quirky, silly, dense, and boring. Her parents fall into the last category, and it's more her nanny (Rosie O'Donnell) who provides the parental safety and caring discipline. Though primarily adventure-packed (in a low-key way), the movie touches also on some more serious topics such as poverty and, especially, the challenge of being your own individual, all in very age-appropriate manner.

While not a loner, Harriet has something she does a lot, and by herself: she spies. After school, she puts on her spy uniform, grabs her essential spy gadgets, and goes spy on her neighbors and classmates. She jots down into her notebook everything she sees. She wants to be a writer when grown up, and for that, she must find out and remember everything. When, however, her friends one day discover her sometimes cruelly honest remarks about themselves, Harriet finds herself alone against everybody else.

Few movies show children being as genuinely children as Harriet the Spy does, and it's easy to imagine the target audience identifying with an adventurous spy. While the movie's IMDB score is poor at the first glance, it's in fact fairly good for females under 18 (the youngest category reported).

Michelle plays Harriet wonderfully effortlessly. The many witty lines seem completely natural, and Harriet's level of energy can't possibly be pretended unless the actress has it genuinely in herself.

The movie is fairly faithful to Louise Fitzhugh's book, although simpler and lacking many of Harriet's deliciously insightful observations. Even then, Harriet the Spy is among the very best in kids' movies.