Background: Bystander-initiated cardiopulmonary resuscitation (CPR) and the use of automated external defibrillation (AED) is pivotal in the community chain of survival, but little is known regarding the bystander experience of performing CPR and AED, and their psychological influence from the incidents in the Asian community. This qualitative study was conducted to explore the experiences of lay rescuers who had performed CPR and AED in public locations in Taiwan. Methods: Lay rescuers who had provided initial CPR and defibrillation with AED in public locations across Taiwan in 2015 were selectively recruited from Taiwan Public AED Registry for a semi-structured interview. Results: Nine participants were included in the study, and event-to-interview duration was within 1 year (n = 4) and 1-2 years (n = 5). The major findings from the study were: (1) the lay rescuers possessed helping traits and high motivation; (2) the lay rescuers reported certain aspects of rescue reality that differed much from prior training and expectations, including difficulty in the depth of chest compression, and uncertainties in real emergency situations; (3) the lay rescuers gained positive personal fulfillment in sharing their experience and receiving positive feedback from others, and were willing to help next time, although they experienced a short-term negative psychological impact from the event. Conclusions: This study provides valuable information on strategies to increase layperson CPR rates and effectiveness in CPR training. Measures should be taken to increase layperson's confidence and situation awareness, reduce training-reality discrepancy, build up a support system to avoid negative psychological effects, and prepare lay rescuers for the next resuscitation.