Survival in acute lymphoblastic leukemia (ALL) has improved in recent decades due to recognition of the biologic heterogeneity of ALL, utilization of risk-adapted therapy, and development of protocols that include optimized chemotherapy combinations, effective central nervous system (CNS) prophylaxis, post-induction intensification of therapy, and a prolonged maintenance phase of treatment. Recent molecular studies have yielded novel insights into both leukemia biology and host pharmacogenetic factors; also, large cooperative group clinical research studies have successively refined effective treatment strategies. While children have higher remission and cure rates than adults, both populations have benefited from these discoveries and innovations. Future challenges in this field include improving outcomes for high-risk patients and those with relapsed disease, and developing and integrating novel targeted therapeutic agents into current regimens to reduce toxicities while further improving outcomes.