An exemplary support mechanism for a portable electronic device includes a seat, a button, a support member, and a hinge assembly. The seat defines a cavity. The button is received in the cavity. The support member includes a knuckle portion. The knuckle portion is received in the cavity. The button abuts against the support member. The hinge assembly connects the knuckle portion to the seat. When the button is pressed to force the hinge assembly to unlock, the hinge assembly drives the support member to rotate.