Celebrity endorsement is a global billion-dollar business used by food, beverage and restaurant companies to influence dietary behaviors that may contribute to overweight and obesity. Evidence suggests that existing government policies and industry self-regulatory programs in the United States (US) do not adequately protect young Americans from celebrity endorsement that promotes energy-dense and nutrient-poor food and beverage products. This PhD dissertation describes four studies that examine the nature, extent, and perceived influence of celebrity endorsement used by business firms and non-profit organizations to promote branded food and beverage products or branded campaigns to American children, adolescents and millennial young adults to inform future research and policies to promote healthy food environments. Study one created a database of US celebrities (n=732) involved with food and beverage group, brand or product endorsements (1990-2017) to examine celebrity profiles and their endorsement relationships, company partnerships, the nutritional profile of products and brands. Evidence was analyzed using Python version 3.5.5 and SPSS version 24. Study two examined celebrities associated with the Partnership for a Healthier America's Fruits and Veggies (FNV) Campaign (2015-2016). Evidence was analyzed using data visualization tools supported by Python and SPSS, and results informed the FNV Campaign. Study three used Q methodology to explore the views of Millennials, born 1981-1994 (n=40) at Virginia Tech about celebrity endorsement of food and beverage products and brands. Participants sorted 48 celebrity images depicting brand and product endorsements on a normal distribution (+4 to -4) based on celebrity trustworthiness and complete a post Q-sort questionnaire. Data analysis used PQMethod 2.35 statistical software program, centroid factor analysis, and qualitative interpretation of unique factor arrays for sorters. Study four identified relevant evidence about US celebrity endorsement of food and beverage products (2000-2019), used an accountability framework to evaluate the adequacy of accountability structures, and suggested future policies and action needed for diverse stakeholders to use celebrity endorsement to promote healthy food environments. Future research should explore the trend of celebrity endorsement used in the US marketplace and examine the influence of this marketing strategy on young people's food preferences and choices based on more representative experimental research. / Doctor of Philosophy / Celebrity endorsement is a marketing strategy that represents a person who uses public recognition to promote the sales, use or consumption of a brand, product, or service. Celebrity endorsement has been used by food, beverage and restaurant companies to influence eating behaviors that may contribute to overweight and obesity. Evidence suggests that existing government policies and industry self-regulatory programs in the United States (US) do not adequately protect young Americans from celebrity endorsement that promotes energy-dense and nutrient-poor food and beverage products. This PhD dissertation describes four studies that examined the nature, extent, and perceived influence of celebrity endorsement used by business firms and non-profit organizations to promote branded food and beverage products or branded campaigns to American children, adolescents and millennial adults to promote healthy food environments. Study one created a database of US celebrities (n=732) involved with food and beverage group, brand or product endorsements (1990-2017) to examine celebrity profiles and their endorsement relationships. Evidence was analyzed using Python data visualization tools and SPSS statistical software. Study two examined celebrities associated with the Partnership for a Healthier America's Fruits and Veggies (FNV) Campaign (2015-2016). Evidence was analyzed using baseline celebrity data (n=82) provided by the campaign initiator, and results informed the FNV Campaign. Study three used Q methodology to explore the views of Millennials, born 1981-1994 (n=40) at Virginia Tech about celebrity endorsement of food and beverage products and brands. Participants sorted 48 celebrity images depicting brand and product endorsements based on celebrity trustworthiness and complete a post Q-sort questionnaire. Data analysis used PQMethod 2.35 statistical software to generate shared viewpoints. Study four identified relevant evidence about US celebrity endorsement of food and beverage products (2000-2019), used an accountability framework to evaluate the adequacy of accountability structures, and suggested future policies and action needed for diverse stakeholders to use celebrity endorsement to promote healthy food environments. Future research should explore the trend of celebrity endorsement used in the US marketplace and examine the influence of this marketing strategy on young people's food beverage preferences and choices based on more representative experimental research.