Abstract: A quick release trailer jack comprises a vertical support mast extending through a jack body. Pinion and worm gears housed in the body couple a crank to a rack gear on the mast for vertically raising and lowering the mast relative to the trailer. A plunger coaxial with the pinion gear permits an operator to axially translate the pinion gear lateral the mast axis, thereby decoupling the crank from the rack gear. The pinion gear slides into a cylindrical cavity containing a biasing spring which returns the pinion gear into its normal position, re-coupling the crank and the rack, when the operator releases the plunger.