<p>This study investigates the impact of institutional pressures, organizational culture, and individual-level factors on the adoption of AI for strategic planning and decision-making activities among marketing employees, with a focus on the moderating roles of perceived accountability and personal innovativeness on the relationship between AI adoption intention and actual use. We employed an explanatory sequential mixed-method design for the research, combining both qualitative and quantitative methods. Initially, quantitative data was collected via online questionnaire with a sample of 699 Vietnamese marketing employees, analyzed by using the PLS-SEM model. Subsequently, qualitative data from 21 in-depth interviews was used to verify and explain the quantitative findings with more multidimensional perspectives. Quantitative results reveal that coercive pressures significantly drive AI adoption intention, while normative and mimetic pressures have limited effects. Organizational flexibility, top management commitment and support strongly influence AI adoption. About individual-level factors, AI literacy emerged as a critical enabler, whereas AI anxiety posed barriers. Moderating effects demonstrate that high personal innovativeness strengthens the relationship between AI adoption intention and actual use, while high perceived accountability weakens it. Qualitative findings were also discussed. This is the first mixed-method study to address a critical gap in the literature by examining the multifaceted influences on AI adoption in the workplace, particularly within the marketing sector. Through a mixed-method approach, the study offers a comprehensive view of how organizational and individual factors interact to drive AI adoption, providing valuable insights for businesses, policymakers, and researchers aiming to foster successful AI integration.</p>