Mr. Peña Nieto, 46, a lawyer who served as governor of Mexico State, has vowed to continue Mr. Calderón’s efforts to work with American law enforcement agencies to quell the violence linked to drug gangs that has killed tens of thousands in the past several years and tarnished Mexico’s image.

His team has emphasized the need to bolster Mexico’s economy, which rebounded from a recession in 2009 and is now growing faster than that of the United States, thanks to an infusion of new manufacturing plants and other investment.

His administration plans more steps to stimulate the economy, arguing that generating better-paying jobs will go a long way toward reducing violence by providing alternatives to crime for the chronically underemployed.

Mr. Peña Nieto also plans to reorganize the federal security forces and intends to form paramilitary units with police duties to combat violence in rural areas and support local and state police departments that are too corrupt or poorly trained to fight crime.