The antioxidant, antibacterial and photocatalytic activity of gold (Au) nanocatalyst derived utilizing Catharanthus roseus leaf extracts are originally described in this investigation. The colour transformation of the developed gold nanoparticles (AuNPs) was originally validated optically. Besides that, UV–visible spectroscopy and scanning electron microscopy were used to interpret the derived Au catalyst’s emergence, size and structure. The existence of phytochemical constituents essential for the encapsulation, accumulation, bio-reduction and anchoring of AuNPs was established by descriptive preliminary phytochemicals, as proven by the Fourier transform infrared spectrum. Cumulative antioxidants, reducing and 2, 2-diphenyl-1-picrylhydrazyl radical activities have been used to assess the antioxidant effects of the AuNPs and their appropriate leaf extract. In comparison to those associated with plant extract, the Au nanocatalyst exhibited increased antioxidant effects in the antioxidant assessments. When compared to Bacillus subtilis (Gram-positive) assayed by the agar well diffusion approach, the derived AuNPs showed tremendous antimicrobial effects against Pseudomonas aeruginosa (Gram-negative). Interestingly, upon UV-light irradiation, the AuNPs displayed substantial photocatalytic performance in destroying rhodamine B dye for approximately 105 min. Therefore, the C. roseus leaf was found to be an environmentally benign feedstock for the greener synthesis of AuNPs, which can be employed as a powerful antioxidant, antimicrobial and photocatalytic ingredient, and hence is used in an array of applicants to enhance social survival chances.