Tall fescue (Festuca arundinacea) is an agriculturally crucial cool-season grass that widely populates temperate regions and has been cultivated in the United States for use as forage and turf. Tall fescue naturally contains a fungal endophyte (hybrid Epichloë spp.) that provides many abiotic and biotic stress resistances to the host grass. The endophyte is asexual and persists in tall fescue through vertical transmission. While endophyte-free cultivars of tall fescue have been developed, the endophyte remains integral to tall fescue breeding for resilient forage and turf. Artificially associating desirable endophytes with elite cultivars of tall fescue has been the primary method of breeding endophyte-infected varieties. A lack of characterization of novel endophytes has hindered endophyte-infected tall fescue breeding. Robust studies are rare as Epichloë endophytes are challenging to work with in vitro. The work showcased here aimed to provide robust characterization studies of tall fescue endophytes in a multifaceted manner. We aimed to highlight areas of interest for tall fescue producers, including 1) early detection methods for endophytes in seedlings, 2) the potential of novel endophyte strains as a biocontrol method against fall armyworm larvae, and 3) identifying highly transmissible novel endophytes when artificially associated with a new host. We lastly aimed to produce high-quality genome assemblies of select strains of uncharacterized hybrid Epichloë spp. for genome characterization use and evolutionary insight. Through this work, we were able to identify candidate endophyte strains for breeding, improve the efficiency of early endophyte screening and provide new genomic resources and an understanding of hybrid endophytes.