In the evolving wireless communications landscape, addressing the challenges of multipath fading and high mobility remains paramount. This paper introduces the Unified Sequency-Frequency Multiplexing (USFM) framework, a pioneering modulation scheme designed to significantly improve signal robustness and system performance by harnessing the integrated strengths of both sequency and frequency domains. At the heart of USFM lies the Joint Sequency-Frequency Transform (JSFT), a novel mathematical operation that seamlessly merges the characteristics of the Walsh-Hadamard Transform (WHT) and the Fast Fourier Transform (FFT). Through rigorous mathematical modeling, we delineate the theoretical foundation of USFM, supported by theorems and lemmas that underscore its potential to mitigate common channel impairments more effectively than existing modulation schemes. Furthermore, we propose an optimization process, guided by machine learning algorithms, to dynamically adapt the signal based on real-time Channel State Information (CSI), ensuring optimal performance under diverse conditions. Empirical simulations demonstrate the superior performance of USFM in scenarios characterized by Rayleigh fading and Doppler effects, highlighting its advantages in terms of error probability reduction and spectral efficiency. The USFM framework represents a significant leap forward in communication theory and offers practical implications for designing future wireless systems that require high reliability and adaptability.