Jakarta put to death two Australians, a Brazilian, and four Nigerians on a prison island, along with one Indonesian, despite worldwide calls for them to be spared and heartrending pleas from their families.
Canberra recalled its ambassador from Jakarta at what it called the "cruel and unnecessary" executions while the United Nations expressed deep regret.
However Widodo, who took office last year, has been unswayed by the international appeals, insisting that Indonesia is facing an emergency due to rising narcotics use.
Asked about the anger in other countries, he said: "My duty as president of Indonesia is to carry out the law and I'm sure other countries will understand this."
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And he added: "Every day 50 young Indonesians die, in one year that is 18,000 dead. I hope they understand about that."
Widodo was referring to figures that he has often used to back up his claims about Indonesia's drugs emergency, including claims that more than 4.5 million users are in need of rehabilitation.
There has been particular anger in Australia - a neighbour and key ally of Indonesia - at the execution of its citizens, Andrew Chan and Myuran Sukumaran, the ringleaders of the so- called "Bali Nine" heroin-trafficking gang.
Canberra mounted a sustained diplomatic campaign to save the pair, in their 30s, saying they were reformed characters after a decade behind bars.
Meanwhile the Brazilian among the group, Rodrigo Gularte, was delusional and oblivious to his fate until the final moments before he faced the firing squad, according to his priest and a lawyer.
Indonesia had an unofficial moratorium on the death penalty between 2008 and 2012 but resumed executions in 2013.
Widodo has accelerated the death penalty campaign - so far 14 drug convicts have been executed during his presidency, 12 of them foreigners.