An electronic device may include a housing, and a finger sensor carried by the housing to sense a user's finger placement at different rotational angles. The electronic device may also include an orientation sensor carried by the housing to sense an orientation thereof, and a processor coupled to the finger sensor and the orientation sensor. The processor may acquire finger-matching biometric data of the user's finger at an unknown rotational angle relative to a known rotational angle of finger-enrollment data, generate an estimated rotational angle of the acquired finger-matching biometric data and based upon a sensed orientation of the housing, and attempt an authentication of the user based upon the estimated acquired rotational angle.