Heatwaves are periods of unusual heat, whose frequency and intensity is increasing. Heatwaves also translate into emergency healthcare dysfunctions, but evidence on how to mitigate these effects still needs to be provided. This multicentric study aimed to identify the interactions between heatwaves and prehospital emergency medicine (PHEM). After obtaining informed consent, PHEM personnel working full-time in different districts of the Veneto Region, Northern Italy, were recruited. Their perspective was captured through semi-structured interviews and analyzed using content analysis methodology. Thirteen subjects participated in the study. Their insights were categorized into four themes: perception of heatwaves; clinical impact of heatwaves; social factors and heatwaves; heatwaves and emergency medical service (EMS). According to the interviewees, the strain on EMSs during heatwaves may be partially reduced by interventions targeting vulnerable populations, primary care, social networks, and education and information. Specific public health actions could follow the surge science principles of staff, stuff, structure, and system to help policymakers improve EMS surge capacity planning, preparedness, and responses. The present study also identified PHEM vulnerabilities and targets of interventions to implement heat–health action plans, mitigate the risk of prehospital emergency care dysfunction, and improve EMS sustainability and preparedness against heatwaves and the changing climate.