Social media influencers (SMIs) have emerged as pivotal figures in advertising and critiquing products and services. They serve as credible sources, disseminating persuasive messages that significantly influence consumer purchasing behavior, particularly among Millennials. This paper investigates the factors pertaining to SMIs that shape the purchasing behavior of Muslim Millennials in Malaysia towards halal food products. Employing a non-probability sampling method, the study surveyed 403 respondents using Structural Equation Modelling-Partial Least Square (SEM-PLS). Data collection utilised a structured closed-ended questionnaire as the survey instrument. Results indicate that SMIs' expertise impacts consumers' attitudes and behaviors towards halal food products, with expertise serving as the sole mediator. Furthermore, SMIs wield significant influence over consumer purchasing behaviour by disseminating product reviews and advertisements to a broad audience. Factors such as trustworthiness, attractiveness, and expertise among these influencers directly impact the purchasing decisions of millennials. This study makes a significant contribution by enhancing comprehension of the latest digital and social media technologies' relevance and importance.