Little is known about pathways to homelessness among older adults. We identified life course experiences associated with earlier versus later onset of homelessness in older homeless adults and examined current health and functional status by age at first homelessness. We interviewed 350 homeless adults, aged 50 and older, recruited via population-based sampling. Participants reported age at first episode of adult homelessness and their life experiences during 3 time periods: childhood (<18 years), young adulthood (ages 18-25), and middle adulthood (ages 26-49). We used a structured modeling approach to identify experiences associated with first adult homelessness before age 50 versus at age 50 or older. Participants reported current health and functional status, including recent mental health and substance use problems. Older homeless adults who first became homeless before 50 had more adverse life experiences (i.e., mental health and substance use problems, imprisonment) and lower attainment of adult milestones (i.e., marriage, full-time employment) compared to individuals with later onset. After multivariable adjustment, adverse experiences were independently associated with experiencing a first episode of homelessness before age 50. Individuals who first became homeless before age 50 had higher prevalence of recent mental health and substance use problems and more difficulty performing instrumental activities of daily living. Life course experiences and current vulnerabilities of older homeless adults with first homelessness before age 50 differed from those with later onset of homelessness. Prevention and service interventions should be adapted to meet different needs.