Azadirachtin and neem oil, renowned for medicinal and insecticidal properties, were studied for extraction and nanoemulsion synthesis, aiming to address inefficiencies of current extraction and emulsification techniques that impede the utilization of Azadirachtin. The novel aspects include an optimized ultrasonic extraction method for azadirachtin, utilizing a binary solvent system. Additionally, the emulsification of azadirachtin neem oil and its direct application as a bioinsecticide on fenugreek crops demonstrate unique advancements in the study. Response surface methodology and Box-Behnken design optimized extraction parameters such as 35 min time, 0.4 g/mL solid-to-solvent ratio, 40% amplitude, and binary-solvent ratio of 75:25 (v/v) (ethanol:n-hexane). Ultrasound demonstrated superior efficiency with process effectiveness 22 times greater than stirred extraction. The extracted azadirachtin neem oil, superior in yield and potency, underwent concentration and nanoemulsion synthesis via ultrasonication. Stable dispersions over 30 days affirmed nanoemulsion sustainability. Emulsification parameters optimized included stabilizer (acacia gum), stabilizer ratio (2:5:100, solid:oil:water, g:mL:mL), amplitude (40%), and time (40 min). Direct application of emulsion as a bioinsecticide on seasonal fenugreek crops exhibited significant efficacy, enhancing growth and nutritional values (60–100%). Ultrasonication emerged as a superior extraction and emulsification tool, yielding potent azadirachtin neem oil-based emulsions applicable across diverse sectors, including agriculture, food, and cosmetics industries.