BACKGROUND: Veterans with mental illness often have poor employment outcomes. OBJECTIVE: This mixed-methods study sought to understand and describe Veteran perspectives of factors that impact their work success. METHODS: A sample of 40 employed and unemployed Veterans with post-traumatic stress disorder (PTSD) or other severe mental illness (SMI) completed a survey of factors that impact vocational functioning and provided narrative accounts of their most successful and challenging work experiences. RESULTS: Personal motivation, self-efficacy, work skills, interpersonal issues, health, and cognitive problems were rated as most impactful on work. There were no significant differences on ratings of work factors based on employment status. Veterans with PTSD reported significantly more barriers to work success compared with Veterans with SMI, notably, cognitive problems, physical health, and psychological stress. Veterans with SMI were more likely to receive VA vocational services and rated this assistance as beneficial to work success. Narrative findings corroborated the survey results, and yielded additional factors, including economic factors, person/job fit, and Veteran-specific issues. CONCLUSIONS: Several factors substantially impact work success in Veterans with mental illness. Veterans with PTSD and SMI experience a distinct set of barriers and facilitators, suggesting the need for tailoring clinical and rehabilitative services.