Primary female infertility is a complex, multifactorial reproductive disorder influenced by unmodifiable organic etiologies as well as modifiable behavioral and psychosocial factors. This narrative review synthesizes current molecular, cellular and endocrine evidence linking body composition, physical activity, dietary patterns and psychological distress to primary female reproductive dysfunction. We highlight specific physiological pathways, including hypothalamic Gonadotropin-Releasing Hormone (GnRH) pulsatility, the hypothalamic-pituitary-adrenal (HPA) axis, follicular microenvironment oxidative stress and peripheral insulin signaling. Furthermore, actionable clinical guidelines for preconception lifestyle modifications are provided alongside prioritized future research avenues. Routine evaluation of modifiable lifestyle parameters represents an essential component of comprehensive reproductive healthcare.