A disposable hearing device is adapted to be positioned entirely within an ear canal for extended wear therein. The device includes a core assembly and a sealing retainer. The core assembly includes a lateral section of generally oval cross-section and generally elongated cylindrical shape for alignment substantially along the ear canal's longitudinal axis, and a receiver section having a receiver coupled to the lateral section for medial positioning in the ear canal's bony region. The lateral section includes a microphone and a battery assembly, and is dimensioned to avoid occluding the ear canal while it is at least partially laterally suspended therein. The sealing retainer is concentrically positioned over the receiver section, and has a composition to conform to the ear canal's bony region wall to seat the hearing device and acoustically seal it in the ear canal to inhibit feedback therein.