Cryptobranchus alleganiensis alleganiensis (Eastern Hellbender) is a fully aquatic salamander of conservation concern across the southeastern US. Characterization of shelter guarding by males and interspecific behavior during the breeding season in wild populations within the Blue Ridge ecoregion of North Carolina is lacking. To this end, we characterized diurnal video sequences of natural shelter-rock and nest-guarding behavior by male Eastern Hellbenders. We documented several intraspecific behaviors between resident males and nonresident conspecifics (males and females) during the breeding season (late summer to early fall) of 2018–2019 using modified action cameras with 4–6 hour battery life deployed in the French Broad River Basin of western North Carolina. Breeding behavior was documented (gravid females entering shelter) in 5 shelters, with 4 nests later confirmed by researchers. Across 21 unique shelters, we documented several examples of aggressive behaviors by resident Eastern Hellbender males toward conspecifics, including defensive posturing, territorial behavior, fights, biting, and bite-holds. All males occupying shelters (residents) spent the majority of time actively guarding the shelter entrance (81.7% of video) followed by maintenance behavior (e.g., modifying the shelter entrance; 5.3% of video), and short bouts (mean = 3.2 minutes) away from the shelter rock (2.5% of video). This study provides the first quantitative report of male breeding-season behavior across multiple natural shelters using non-invasive, affordable, waterproof cameras in North Carolina. We report on the utility of this method for observing behavior in stream systems and its potential application for monitoring of nests and behavior in other diurnal aquatic species.