The increasing prevalence of cyber threats has heightened the need for integrating security into software development processes. In Agile development environments, where rapid iterations and continuous deployment are prioritized, implementing a Secure Software Development Lifecycle (SDLC) presents unique challenges. This research explores the effectiveness of incorporating security measures within Agile frameworks in U.S.- based organizations. Through an analysis of secure SDLC models and best practices, this study identifies strategies to enhance security without compromising Agile's flexibility. Findings suggest that integrating security at each Agile iteration, adopting DevSecOps principles, and leveraging automated security tools significantly reduce vulnerabilities while maintaining development velocity. This study contributes to the growing body of research on secure Agile development and provides practical recommendations for software development teams.