The 57-year-old Horacio Cartes also is a political neophyte who never registered to vote before running for president, and he's often faced accusations that his family's fortune was fed by money laundering, cigarette smuggling and drug trafficking.
Paraguayan voters overlooked these allegations, focusing instead on hopes that the boyish-looking businessman from the dominant Colorado Party can help the country reap more benefit from windfall soy profits that are boosting the economy at 10 percent a year.
Inaugural organisers said his most important encounter today would be a lunch with 150 foreign executives eager to improve the economic infrastructure in the country of 6.2 million people, where 39 percent of people live in poverty.
"We have declared war on poverty, and from this government we will call no truce," Cartes said in his victory speech.
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His elected predecessor, Fernando Lugo, also promised to combat poverty, and like Lugo, Cartes is a political outsider, having joined the Colorado Party only in 2009.
Smuggling, corruption and tax evasion are endemic in Paraguay, and analysts believe it's difficult for executives not to come in contact with criminals at some point.
The corruption watchdog group Transparency International ranks Paraguay 150th worst out of 176 countries. The U.S. Congressional Research Service reported in 2010 that "corruption is a major impediment to consolidating democratic institutions" in Paraguay.
Accusations involving Cartes became widely reported after WikiLeaks published a 2010 U.S. State Department cable that labelled him the head of a drug trafficking and money laundering operation.