The chair adjustment mechanism, attached beneath a chair arm, has a housing and four walls forming an interior closed space. A closing bottom wall has a longitudinal guide slot. A longitudinal continuous serpentine adjustment cam surface. A cam follower on an adjustment plate moves on the cam surface in the interior space. The adjustment plate movably extends through the guide slot in a close fit and substantially closes the guide slot thereat. In one embodiment, each sidewall defines an opposing cam surface and a pair of cam followers extend laterally from an upper region of the adjustment plate. The lower plate extends outward from the slot and is preferably attached to two chair legs. The adjustment plate moves vertically, first out from the depending cam ridges, then the plate and cam follower moves longitudinally, and then moves vertically into a different intersection between adjacent depending cam ridges.