Macrocyclic pyridone pentamer‐functionalized nanofiber was fabricated through electrospinning for selective heavy metal cation removal from aqueous solution. Parameters influencing the adsorption process, including contact time, initial metal cation concentration, and solution pH, were evaluated, and the optimized adsorption condition was figured out accordingly. The adsorption study demonstrated that the process followed the pseudosecond‐order kinetic models and Langmuir isothermal model. The selectivity of the nanofiber toward metal cations was studied, and it was found that it showed a high adsorption affinity toward Pb2+ over other metal cations such as Cu2+, Ca2+, Co2+, Zn2+, and Ni2+. The nanofiber could be easily regenerated by deadsorption with ethylenediaminetetraacetic acid solution. The above results indicate the potential application of the nanofiber in the metal cation separation field. [ABSTRACT FROM AUTHOR]