Background: Throughout the COVID-19 pandemic, hospital medical staff (HMS) have faced significant personal, workplace, and financial disruption. Many have experienced psychosocial burden, exceeding already concerning baseline levels. This study examines the types and predictors of coping strategies and help-seeking behaviours utilised by Australian junior and senior HMS during the first year of the pandemic. Methods: A cross-sectional online survey of Australian frontline healthcare workers was conducted between 27th August and 23rd October 2020. Data collected included demographics, personal and workplace disruptions, self-reported and validated mental health symptoms, coping strategies, and help-seeking. Results: The 9518 participants included 1966 hospital medical staff (62.1% senior, 37.9% junior). Both groups experienced a high burden of anxiety, depression, post-traumatic stress disorder, and burnout. Coping strategies varied by seniority, with maintaining exercise the most common strategy for both groups. Adverse mental health was associated with increased alcohol consumption. Engagement with professional support, although more frequent among junior staff, was uncommon in both groups. Conclusions: Junior and senior staff utilised different coping and help-seeking behaviours. Despite recognition of symptoms, very few HMS engaged formal support. The varied predictors of coping and help-seeking identified may inform targeted interventions to support these cohorts in current and future crises.