Wool fibers with multifunctional properties are highly in demand for use in different applications. The chemicals used to impart multifunctional properties to wool fibers are environmentally harmful and necessitate multi-step processing to achieve them. In order to endow and improve the effectiveness of the various properties of wool fibers, the current work offers evidence to support the viability of using a quick, efficient, and eco-friendly one-pot approach instead of a multi-step process. This approach enables wool fibers' prospective ability to be used in a wide range of applications, including domestic, industrial, and environmental applications. This approach focused on the facile simultaneous synthesis and immobilization of mono- or bimetallic nanoparticles on the wool fiber surface using the proteins present in the wool fibers as a reducing agent, to reduce metal ions to metal nanoparticles, with simultaneous binding of the formed nanoparticles on the wool fibers surface. First, the wool fibers are added to individual metal salt solutions comprising Ag+, Cu2+, or Fe3+ ions or to mixed metal salt solutions that comprise Ag+/Cu2+, Ag+/Fe3+, and Cu2+/Fe3+ ions. Under the influence of moisture and heat, the proteins (sulfur-containing amino acids (Cysteine)) acted as reduction agents to change the metal ions that have adsorbed on the wool fibers' surface into zero-valent atoms with simultaneous binding on the wool fibers' surface. The nanoparticles-immobilized wool fibers were characterized using SEM, EDX, and FTIR. To investigate the effect of metal nanoparticles on the dyeing process, wool fibers treated with monometallic nanoparticles were subsequently dyed with natural dye (cochineal dye). The results showed that the presence of mono- or bimetallic nanoparticles within the wool fiber surface imparts multifunctional properties to wool fibers. The mono- and bimetallic nanoparticles endowed the wool fiber with different colors depending on the type of metal. The monometallic nanoparticles immobilized on the wool fibers enhanced the dyeing of wool fibers with cochineal dye, with different colors ranging from purple to reddish-purple and acceptable colorfastness properties. The mono- and bimetallic nanoparticles immobilized on the wool fibers' surface enhanced the UV protection, antistatic properties, and antimicrobial activities of the wool fibers' surface. It is considered great that the UPF values for modified wool fibers were 50 and 50 +. Mono- and bimetallic nanoparticles improved the antistatic characteristics of wool fibers, with an average static half-life of less than 1 s. The mono- and bimetallic nanoparticles immobilized on the wool fibers showed excellent antimicrobial activities against Gram-positive bacteria (S. Aureus), Gram-negative bacteria (E. Coli), and fungi (C. Albicans). Furthermore, dyed wool fibers@monometallic nanoparticles showed excellent UV protection very good antistatic behavior and excellent antimicrobial activities. Furthermore, the effectiveness of mono- and bimetallic nanoparticles immobilized on the surface of wool fibers was evaluated for the removal of phenol from fuel. The findings demonstrated that wool fibers immobilized with mono- or bimetallic nanoparticles had a high adsorption potential and could be employed as a removable substrate for fuel purification. Wool fibers treated with mono- or bimetallic nanoparticles proved to be greatly promising for versatile applications, as well as a value-adding material for different fields. In this way, they can be used for multipurpose applications ranging from protective clothing to technical textiles, and environmental applications.