Objective: The present study aims to assess the mental health of Chinese people during the Omicron variant outbreak in March 2022. This study also explores how coronavirus disease 2019 (COVID-19) exposure history, vaccination status, sleep quality, and alcohol dependency symptoms influence mental health outcomes. Methods: The data were collected from 1049 Chinese people through Tencent using a structured questionnaire utilizing convenience sampling technique. The online cross-sectional study included the Chinese version of the Depression, Anxiety and Stress Scale 21, the Alcohol Use Disorder Identification Test, Fear of COVID-19 Scale, Warwick Edinburgh Mental Well-being Scale, and Pittsburgh Sleep Quality Index to assess depression, anxiety, stress, alcohol dependency, fear of COVID-19, and sleep quality, respectively. Statistical analyses included independent sample t-tests and chi 2 tests to assess the differences in study variables across demographic characteristics, and multiple linear regressions to assess the effect of the experience of COVID-19 infection, vaccination, and mental health variables on sleep quality and alcohol dependency. Results: Results showed that 11.5% to 32.4% of the participants had a poor mental health symptoms. Males had significantly higher depressive symptoms (chi(2)= 12.283, df = 4, P = .015) and alcohol dependency symptoms (chi(2)= 66.604, df = 3, P < .001), and females had significantly lower mental well-being (chi(2)= 12.742, df = 2, P = .002). Additionally, findings showed that stress (beta = .250, P < .001), mental well-being (beta = -.166, P < .001), and fear of COVID-19 (beta = .061, P = .029) predicted poorer sleep quality, and anxiety (beta = .115, P = .035) and mental well-being (beta = -.097, P = .002) predicted alcohol dependency symptoms. Conclusion: Since the pandemic-induced mental health challenges persist for a prolonged period, the findings of these relationships offer guidance for mental health professionals to formulate therapeutic interventions to help people cope with psychological crises.