Thailand's educational policy emphasizes integrating Sufficiency Economy Philosophy into education management systems at all levels, including teacher preparation programs that develop educators capable of serving as role models for sustainable living. This research aimed to: 1) assess the needs for developing and promoting student teachers' application of Sufficiency Economy Philosophy, and 2) propose guidelines for cultivating sufficiency characteristics and integrating Sufficiency Economy Philosophy into teacher education curriculum and training processes. The research employed a cross-sectional survey design with 180 student teachers from teacher education institutions in Thailand. Data were collected using a validated and reliable questionnaire developed from the Sufficiency Economy Philosophy conceptual framework, covering nine dimensions of competency. Data analysis utilized descriptive statistics (means and standard deviations) and the Modified Priority Needs Index (PNI[subscript Modified]) to identify developmental priorities. Results revealed that current Sufficiency Economy Philosophy implementation levels ranged from moderate to high (mean scores 3.36-3.59), while desired competency levels ranged from high to highest (means 4.39-4.60), indicating significant developmental gaps. Priority developmental needs identified through PNI[subscript Modified] analysis included: 1) risk prediction and readiness for change (good built-in immunity) (PNI[subscript Modified] = 0.32), particularly developing the ability to cope with potential future negative consequences (PNIModified = 0.35) and knowing what actions to take to prevent problems or resolve issues that may arise (PNI[subscript Modified] = 0.33); 2) evaluation and improvement of practical thinking (performance and work evaluation) (PNI[subscript Modified] = 0.30), especially identifying problems related to lack of virtues and determining strategies for improvement (PNI[subscript Modified]= 0.33); and 3) reflective thinking and learning summary (learning summary) (PNI[subscript Modified] = 0.27), including extracting lessons related to balance across four dimensions (PNI[subscript Modified] = 0.32). The findings reveal significant competency gaps requiring systematic curriculum development. Guidelines recommend integrating self-immunity skills through experiential learning approaches, with priority given to developing risk management capabilities, reflective assessment skills, and ethical reasoning competencies.