Ultrasound-assisted extraction for bioactive compound retrieval is a viable alternative to traditional extraction methods. Employing ultrasound-assisted extraction, this study aimed to enhance the scavenging capacity of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothia-zoline-6-sulfonic acid) (ABTS), total polyphenol content (TPC), and flavonoid content in Ainsliaea acerifolia (A. acerifolia) through response surface methodology (RSM). Initially, the impact of extraction temperature, time, and ethanol concentration on DPPH scavenging capacity, ABTS, TPC, and flavonoid content was assessed. Optimal conditions for maximizing antioxidant activity and TPC were determined as 78% (v/v) ethanol, 60 °C extraction temperature, and 91 min of extraction time. High-performance liquid chromatography (HPLC) analysis of the optimized extract revealed dicaffeoylquinic acid as the primary polyphenol in A. acerifolia extracts, comprising the majority of phenolic compounds (102.06 mg/g DW). This model enabled the optimization of conditions for phenolic compound extraction with antioxidant properties from A. acerifolia, highlighting its potential as a source of antioxidant compounds for industrial, pharmaceutical, and food applications.