Objectives The objectives of this study were to compare the prevalence of three positive mental health (PMH) outcomes (self-rated mental health, life satisfaction, sense of community belonging) in postpartum women to the general population, and to examine the relationship between protective factors and the three PMH outcomes among postpartum women. Methods The national cross-sectional Survey on Maternal Health (n = 6558) was analyzed. Analyses were weighted and 95% confidence intervals were calculated. Three adjusted logistic regression models were generated. To compare this sample to the general population of women, estimates from the Canadian Community Health Survey-Annual Component (2018) were used. Results Compared to the general population of women, a larger proportion of postpartum women reported a strong sense of community belonging. The odds of postpartum women with high self-rated physical health having high self-rated mental health were approximately seven times greater (aOR 6.9, 95% confidence interval [CI] 5.9, 8.1) than postpartum women with lower self-rated physical health. The absence of symptoms of postpartum depression (PPD) or generalized anxiety disorder (GAD) and high self-rated physical health were significantly associated with all three PMH outcomes. Frequent availability of maternal support was associated with greater odds of high life satisfaction (aOR 1.6, 95% CI 1.4, 1.9) and sense of community belonging (aOR 1.4, 95% CI 1.2, 1.6). Conclusions Our study demonstrated that availability of maternal support, self-rated physical health and absence of symptoms of PPD or GAD were associated with PMH among postpartum women. As physical health had the strongest association with mental health, we encourage further examination of this relationship.