This chapter explores the complex relationship between plants and endophytes, focusing on fungal endophytes and soilborne fungi. It explores the multifaceted roles of endophytes in promoting plant growth, enhancing resistance to abiotic stress, and aiding in defense against pests and diseases. The significance of bacterial endophytes, such as their resistance to metal toxicity, is highlighted. The research emphasizes the escalating threat of soilborne phytopathogens, particularly fungal species, to global crop production and food security. Additionally, the biocontrol potential of fungal endophytes, their metabolites, and mechanisms such as competition, induced resistance, mycoparasitism, and antibiotics are discussed, offering promising avenues for sustainable agriculture. This comprehensive chapter focuses on the isolation, identification, and application of fungal endophytes for biocontrol in agriculture. The process involves surface sterilization of plant parts, various isolation methods, and morphological identification. The interaction dynamics between endophytes and host plants are explored emphasizing their potential as biocontrol agents (BCAs). Challenges, such as host specificity and environmental adaptation, are discussed. Successful applications, particularly direct antagonism to pathogens and systemic resistance induction, are highlighted. The chapter underscores the environmental and safety considerations of using fungal endophytes emphasizing reduced chemical use and the need for ongoing research and monitoring. Future prospects include sustainable agriculture, efficacy improvement, and multi-omic approaches.