Pete Black is a student at Stoneybrook Middle School in the same grade as the older BSC members.
He eats lunch at the mixed-gender table where Claudia and Stacey sit before they begin eating with the other BSC members. He often uses the cafeteria food to make food sculptures, along with Howie Johnson and Rick Chow.
In book #2, he asks Stacey to the Halloween Hop. They begin talking on the phone regularly and she calls him her "sort of boyfriend." They go together to the Snowflake Dance and the Final Fling, although by that time Stacey suspects he may be interested in Dorianne Wallingford. He's dating Dorianne by #10, when Claudia tells a story in a BSC meeting about Pete taking Dorianne to the movies and snapping her bra strap. (Mary Anne observes internally that Pete was always doing that, "just to be mean." In #46, she recalls a story about him breaking Miranda Shillaber's bra strap while snapping it during class.) Stacey still invites both Pete and Dori to the party at her house.
In #46, Mary Anne Misses Logan, Pete is part of Mary Anne's study group along with Logan and Cokie Mason, researching the books of Megan Rinehart. At first he dismisses her books as "for girls", but eventually agrees to read four of them over a two-week period and admits afterward that he enjoyed them. Since Logan and Cokie seem to be ignoring the assignment, he and Mary Anne team up to complete it (although it turns out to be unnecessary).
Pete runs for class president against Kristy, Grace Blume and Alan Gray in #53, Kristy for President. Kristy originally dismisses Pete as immature, but grows to respect his campaign and endorses him when she drops out of the running. He subsequently wins the office.
Pete has told Claudia that she's "awesome-looking." He's friends with Alan Gray and Justin Forbes, as well as Robert Brewster, Stacey's boyfriend in later books, and Logan. He has brown hair which he lets grow longer over the summer preceding book #99.
He helps out with the inauguration of the recycling program at SMS in #57. He goes with Dawn to the January Jamboree in #60. In #85, he and Erica Blumberg audition to host a radio show segment called "Bike Advice." He comes to Claudia's party in #123.