<p>Cellulose, a biodegradable and renewable material, is versatile and transforms various fields. This work uses a chemo-mechanical method to discuss the extraction and analysis of palmyra (<i>Borassus flabellifer)</i> fruit derived cellulose nanofibers (PFCNF). The mild acid treatment, steam explosion, and homogenization could increase the physico-chemical properties of <i>Borassus flabellifer</i> fiber. The chemical composition and FTIR analysis confirmed the successful elimination of the hemicellulose, lignin, and other extractives in the palmyra fruit pulp. The solid-state ¹³C NMR proved the cellulose type I structure of the extracted PFCNF. The crystallinity index of PFCNF was found to be 57%. The yield of the cellulose was calculated to be 44%. PFCNF exhibited fibrous morphology with a nanodimension of 10–80 nm, validated using scanning electron microscopy and transmission electron microscopy. With progressive treatments, the thermal stability was increased, and the <i>T</i>_max of PFCNF was 32 ℃ higher compared to the raw fibers. These superior properties further support their potential in eco-friendly packaging, advanced composites, biomedical materials, film production, electronics, coating materials, and paper production.</p> Graphical abstract <p></p>