In this study, we investigated in vitro the potential ofTrichoderma harzianumto produce bioactive secondary metabolites that can be used as alternatives to synthetic compounds. The study focused on analyzing two extracts ofT. harzianumusing ethyl acetate andn-butanol solvents with different polarities. The extracts were examined using phytochemical analysis to determine the content of polyphenols, flavonoids, tannins, and alkaloids. Thin-layer chromatography (TLC) and Gas chromatography-mass spectroscopy (GC-MS) analysis were used to profile volatile organic metabolites (VOCs) present in the extracts. Furthermore, the extracts were tested for their antifungal ability using the poison food technique. For measuring antioxidant activity, the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) test was used.Trichoderma harzianumwas shown to have a significantly high content of tannins and alkaloids, with a noticeable difference between the two extracts. GC-MS analysis identified 33 potential compounds with numerous benefits that could be used in agriculture and the medicinal industry. Moreover, strong antifungal activity was identified againstSclerotinia sclerotiorumby 94.44%,Alternariasp. by 77.04%, andFusarium solaniby 51.48; similarly, the IC50of antioxidant activity was estimated for ethyl acetate extract by 71.47% andn-butanol extract by 56.01%. This leads to the conclusion thatTrichoderma harzianumVOCs play a significant role as an antifungal and antioxidant agent when taking into account the advantageous bioactive chemicals noted in the extracts. However, to our knowledge, this is the first study in Algeria presenting detailed phytochemical analysis and GC-MS profiling ofTrichoderma harzianumfor two extracts, ethyl acetate andn-butanol.