Jeffy is recognizable among the Three J's due to his brown/reddish hair. He is part of the football team.
He has a small entry in The Daria Diaries. His surname was never mentioned in the episodes nor in the books.
In Lucky Strike, he manages to get a good grade on the Romeo and Juliet test Daria gives. She says his theory about Mercutio having "a thing" for Romeo was well-argued, though a tangent about keeping gays out of the locker room was "a little narrow-minded."
In One J at a Time, Jeffy quite rapidly socialized with Tom Sloane and Jake Morgendorffer, brainstorming how to catch a squirrel (he'd done it before at some point); when Quinn asked him whether it was more important to stay with their date or capture a squirrel, he joined the lads when the squirrel was spotted. They then went on to have a fun night out of male bonding. He also showed to be a fan of the song Whomp! There It Is by Tag Team, and used to go go-karting with his father at a go kart track just outside of Lawndale County.
Quinn is Jeffy's ultimate crush; he and the Three J's follow her around like sheep. He is willing to do practically anything for Quinn, and the two even date at one point; in One J at a Time, Jeffy has the distinction of being the only one of the Three J's to go to a Morgendorffer dinner as Quinn's date. However, it should be stressed that this happens only after Quinn has dumped both Joey and Jamie.
The three boys collectively are known as the Three J's. All the boys are on the football team, and they fight for Quinn's love and attention as well as tease each other near constantly.