The imminent threat of quantum computing to traditional cryptographic foundations necessitates a strategic evolution of enterprise network architectures. This article presents a comprehensive framework for designing and implementing post-quantum cryptography (PQC) within modern network infrastructures, with particular emphasis on enterprise zero-trust environments. Beginning with an assessment of NIST-standardized quantum-resistant algorithms, including CRYSTALS-Kyber and Dilithium, the article evaluates their suitability for enterprise deployment based on security characteristics, performance attributes, and implementation considerations. A structured approach to PQC integration is proposed, encompassing hybrid cryptographic models for transitional security, protocol-specific integration patterns, certificate lifecycle management adaptations, and hardware security module considerations. The framework extends to zero-trust architectures, detailing implementation strategies for SaaS environments, cloud provider readiness assessment methodologies, endpoint security enhancements, and regulatory compliance mechanisms. Through a detailed case study of an enterprise PQC transition, the article demonstrates the operational impact, performance characteristics, and security benefits of systematic quantum-resistant cryptography deployment, providing actionable insights for organizations preparing for post-quantum security challenges.