Background/Objectives: In-hospital cardiac arrest (IHCA) remains associated with poor survival, while the contribution of arrest etiology and early physiological markers to outcome remains incompletely defined. We examined associations between clinical, neurological, metabolic, and etiological factors and sustained return of spontaneous circulation (ROSC) lasting >20 min, 28-day survival, and 60-day mortality. Methods: This retrospective single-center cohort included 134 adults with confirmed IHCA requiring cardiopulmonary resuscitation at a tertiary university hospital with advanced transplant care between 2011 and 2015. Sustained ROSC and 28-day survival were analyzed using parsimonious Firth penalized logistic regression models, and 60-day mortality using Cox proportional hazards regression. Selected neurological and biomarker analyses were considered exploratory. Results: Sustained ROSC was achieved in 91 patients (67.9%), 33 (24.6%) survived to day 28, and 30 (22.4%) survived to day 60. Initial non-shockable rhythm was associated with lower odds of sustained ROSC (aOR 0.26, 95% CI 0.09–0.69) and 28-day survival (aOR 0.27, 95% CI 0.10–0.68), and with higher 60-day mortality (aHR 1.96, 95% CI 1.25–3.08). The presence of a potentially reversible cause was associated with more favorable outcomes, whereas active hematologic malignancy was associated with higher 60-day mortality (aHR 1.89, 95% CI 1.15–3.10). Exploratory analyses also showed associations of initially dilated pupils with lower 28-day survival and higher lactate with 60-day mortality. Among patients who survived beyond 24 h, higher BNP was associated with subsequent mortality. Conclusions: Non-shockable rhythm and the presence of a potentially reversible cause were consistently associated with outcomes following IHCA, while active hematologic malignancy was associated with poorer longer-term survival. Exploratory findings from lactate, initial pupillary assessment, and BNP may provide complementary prognostic information, although the BNP analysis was limited to patients who survived beyond 24 h. These findings require confirmation in contemporary multicenter cohorts and do not establish validated clinical prediction tools.