Yes! If newly-elected Rep. George Santos (R-NY) goes to prison — which is a possibility, see story here — he could still serve in Congress, but presumably would vote remotely, and participate in committees via Zoom. Arrangements could be made to wire his cell for videoconferences, so he could meet with lobbyists and constituents.
In 1798, Mathew Lyon of Kentucky was elected to Congress while in jail for criticizing the president, which was prosecutable sedition in those days (a law Trump no doubt would’ve liked to seen reinstated). He also spat on another congressman (see details here), but that was a minor offense in those days.
It’s not like Congress has ever been a deliberative body. It’s a breeding ground for criminals. Most of them, though, go to prison after being elected. (See list of recently indicted congressmen and senators here; for historical list, go here).
Image below: Artist’s drawing of the 1798 Congress in session
