This study used a Delphi survey to define the concept of oral function rehabilitation exercise (OFRE) based on the International Classification of Functioning, Disability, and Health (ICF) and to categorise intervention domains for community-dwelling older adults. While numerous studies have been conducted to improve oral function through exercise interventions, the conceptual definition of oral exercise remains unclear and there is a lack of systematic categorisation of oral exercise intervention domains. A preliminary model was developed based on the key findings of 19 papers selected from a prior systematic review. Its validity was confirmed through a Delphi survey conducted twice with eight expert panellists. Consensus was achieved by evaluating the validity of the OFRE conceptual framework, the accuracy of OFRE conceptual definitions, and intervention domains. Through expert consensus, an ICF-based OFRE conceptual framework was developed that includes 21 factors that affect the oral health status of the older adults. The OFRE intervention domain for improving the health status consisted of oral function rehabilitation warm-up exercise, masticatory function exercise, swallowing function exercise, articulatory function exercise, salivary function exercise, and oral function rehabilitation cool-down exercise, and 11 specific intervention methods were derived. The OFRE intervention can be used for planning and applying successful interventions to improve oral function and life function of older adults.