<p>In the evolving field of intelligent healthcare systems, secure and efficient communication is critical. This paper proposes a three-factor authentication protocol designed for 6G-enabled healthcare environments that merges smart cards, passwords, and biometrics to ensure robust security. To enhance performance, the protocol makes use of Chebyshev chaotic maps for key generation and lightweight encryption techniques. It introduces a fast authentication mechanism through parameter reuse achieving reduced latency and eliminates the need for a pre-established secure channel during registration, making deployment more practical. Furthermore, the scheme incorporates a certificate-less, user-centric framework for multi-server healthcare systems. Formal security verification using Scyther confirms the protocol’s resilience to various attacks, including replay, man-in-the-middle, and impersonation attacks. Comparative analysis demonstrates its effectiveness in terms of security, communication efficiency, and computational cost, achieving an average authentication time of <b>0.00354 ms</b> and a 57% reduction in storage cost. These results make it a viable solution for healthcare applications in resource-constrained and latency-sensitive environments.</p>