Objective: To determine if synchrony in emotional arousal and affective regulation between patients and clinicians reflect emotional bonding during emergency behavioral health appointments. Method: Audio recordings of suicide risk assessment interviews and crisis intervention planning with 54 suicidal active duty soldiers presenting to an emergency department or behavioral health clinic were analyzed. Emotional arousal was assessed using mean fundamental frequency. Patient-rated emotional bond was assessed with the Working Alliance Inventory, Short Form (Hatcher & Gillaspy, 2014). Actor-partner interdependence modeling was used to identify moment-to-moment patterns of covariance among clinician and patient emotional arousal. Results: Greater synchrony in clinician and patient emotional arousal was positively associated with higher emotional bond ratings during the crisis intervention but not the risk assessment interview. During the risk assessment interview, higher emotional bond was associated with a dysregulating effect of the clinician on the patient’s emotional arousal (i.e., larger fluctuations in the patient’s emotional arousal). The reverse pattern was seen during the intervention: Higher emotional bond was associated with a regulating effect of the clinician on the patient’s emotional arousal (i.e., smaller fluctuations in the patient’s emotional arousal). Emotional bond during the intervention was also positively associated with a regulating effect of the patient on the clinician’s emotional arousal. Conclusion: Emotional bonding during emergency clinical encounters is associated with patient–clinician synchrony in emotional states. During crisis interventions, emotional bonding is also associated with mutual down-regulation of emotional arousal among patients and clinicians.