Background: Acceptance of vaccination in both healthcare professionals and the general public in the community is vital for efficacious control of the virus. Vaccine acceptance associates with many factors. Little research has been dedicated to examining attitudes and behaviors of healthcare professionals and community stakeholders regarding COVID-19 vaccine acceptance in Hong Kong. Methods: An online cross-sectional survey was sent between February and April 2021 (N = 512). Multivariable regression modeling was used to identify associated variables with outcomes using adjusted odds ratios (AOR) and 95% of confidence intervals (CI). Results: Two demographic variables—age group of over 40 years old (40–59: ORm = 3.157, 95% CI = 2.090–4.467; 60 or over: ORm = 6.606, 95% CI = 2.513–17.360) and those who had previously received a flu vaccination (ORm = 1.537, 95% CI = 1.047–2.258)—were found to be associated with high vaccine intent. Adjusting for these two variables, the results showed that five factors on knowledge variables as perceived benefits for vaccine intent were statistically significant: “Closed area and social gathering are the major ways of SAR-CoV-2 transmission” (AOR = 4.688, 95% CI = 1.802–12.199), “The vaccine can strengthen my immunity against COVID-19, so as to reduce the chance of being infected with it” (AOR = 2.983, 95% CI = 1.904–4.674), “The vaccine can lower the risk of transmitting the viruses to my family and friends” (AOR = 2.276, 95% CI = 1.508–3.436), “The benefits of COVID-19 vaccination outweigh its harm” (AOR = 3.913, 95% CI = 2.618–5.847) and “Vaccination is an effective way to prevent COVID-19” (AOR = 3.810, 95% CI = 2.535–5.728). Conclusions: High vaccine intent was associated with age and having previously received a flu vaccination. Knowledge and attitudes of healthcare professionals and community stakeholders were associated with high vaccine intent. Training and continuing education programs for healthcare providers and community stakeholders focusing on the delivery of evidence-based data on the benefits of vaccination campaigns for populations to increase the vaccination rates is recommended.