Adolescent liver health is negatively affected by obesity-related fatty liver disease. Researchers used transient elastography to analyze the prevalence and correlations between hepatic steatosis, fibrosis, body composition, and lifestyle factors in a sample of American adolescents. During the 2017–2018 National Health and Nutrition Examination Survey (NHANES), 1,080 male and female adolescents (12–19 years old) from various racial and ethnic backgrounds were tested for liver stiffness and the controlled attenuation parameter (CAP). Anthropometry and dual-energy x-ray (DXA) absorptiometry were used to measure the participants. The average CAP of boys was 223.7 dB/m, which was significantly higher than that of girls (215.3 dB/m) (5.1 kPa vs. 4.9 kPa). There was a strong correlation between BMI and both CAP and hepatic stiffness. High CAP in the upper quartile was linked to being Hispanic or non-Hispanic Asian, having a higher body mass index (BMI), waist-to-hip ratio (WHR), systolic blood pressure (SBP), and amount of time spent sitting, and having a lower amount of time spent being physically active and having a lower Healthy Eating Index-2015 score, after controlling for other factors. Higher levels of liver stiffness were linked to being male, being of non-Hispanic black ethnicity, and having a higher body mass index, alanine aminotransferase, cytoplasmic alkaline phosphatase, and serum cotinine in multivariate analyses. Multivariate analysis revealed a positive association between DXA total percent fat and percent trunk fat and CAP (P<0.001 for each), but not with liver stiffness. Consistently adverse events and liver stiffness both performed similarly as continuous variables. Higher levels of CAP and hepatic stiffness were connected to increased anthropometric and DXA body composition measurements and lifestyle variables in US teenagers. In high-risk children, transient elastography and other noninvasive markers may be used to diagnose the liver disease at an early stage.