Herbert "Herb" Jacob is Junie B.'s best friend in first grade. They sit next to each other on the bus on the way to and from school. He seems to dislike May as much as Junie B. does. In Junie B. Top Secret Personal Beeswax, he and Junie B. seem to have a crush on each other.
Herb is shown to be helpful and a good friend. As seen in "Junie B., First Grader: Cheater Pants" he heard Junie B. struggling and gave her his answer on the test, although Junie B. failed. He also gave Junie B half his sugar cookie in "Junie B., First Grader: Boss of Lunch" so that's how caring he is. While he is much calmer than Junie B., he is very happy-go-lucky and roots for Junie B. and enjoys her humor.