<P> In the final episode of the series , it is revealed that Jenny knew that her brother , Dan Humphrey , was the mysterious blogger behind Gossip Girl . She returns to the Upper East Side , appearing in the five - year time jump for her brother 's wedding to Serena van der Woodsen . Jenny works as a designer for Blair 's fashion empire , implying that they have gotten over their past animosity . Together they create their own clothing line , `` J for Waldorf '' . </P>
when does jenny come back to gossip girl
the final episode of the series