The current study presents novel, green, and mycosynthesized silver nanoparticles (NPs) for various biomedical and environmental applications, using the biosource Daedalea sp. In the study, AgNO3 was converted into stable elemental silver (Ag0) at a nanometric scale using a aqueous extract of Daedalea sp mushroom. The NPs were extremely pure and stable, with an average size of 24.3 nm and an irregular morphology. A wide range of biomedical applications, such as bactericidal, fungicidal, leishmaniasis, antioxidant, anti-diabetic, and biocompatibility studies, made use of the characterized nanoparticles. Our research revealed that MDR bacterial strains and spore-forming fungal strains were both highly responsive to Daedalea sp mediated AgNPs. All of the tested UTI bacterial isolates were resistant to non-coated antibiotics, but by adding 1% of the synthesized AgNPs, the antibiotics' bactericidal potential was greatly increased. The NPs also demonstrated dose-dependent cytotoxic activity against Leishmania Tropica, with significant LC50 values for promastigote and amastigote parasites of 248 and 251 g/mL, respectively. Additionally, significant inhibition of -amylase, -glucosidase, acetylcholinesterase (AChE), and butrylcholineterase (BChE) were noted, suggesting possible disease and anti-diabetic effects. Additionally, the particles' remarkable biocompatibility with human red blood cells was discovered. The photocatalytic activity of mycosynthesized AgNPs resulted in 98.2% degradation of indigo carmine dye in 140 minutes. Daedalea sp AgNPs can be used as novel candidates for a variety of biomedical and environmental applications due to their eco-friendly synthesis, biosafe nature, and excellent physicochemical properties.