A biological method was successfully applied to synthesize spherical silver nanoparticles (AgNPs) while using the extract of lavender (Ex-L) (lat. Lavandula angustifolia) as the reducing and stabilizing agent. The produced nanoparticles were spherical with an average size of 20 nm. The AgNPs’ synthesis rate confirmed the extract’s excellent ability to reduce silver nanoparticles from the AgNO3 solution. The presence of good stabilizing agents was confirmed by the excellent stability of the extract. Nanoparticles’ shapes and sizes did not change. UV-Vis absorption spectrometry, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were used to characterize the silver nanoparticles. The silver nanoparticles were incorporated into the PVA polymer matrix by the “ex situ” method. The polymer matrix composite with AgNPs was prepared in two ways: as a composite film and nanofibers (nonwoven textile). The anti-biofilm activity of AgNPs and the ability of AgNPs to transfer toxic properties into the polymer matrix were proved.