•Mr Bukele - who calls himself the world's coolest dictator - was re-elected for a second term this month.
•Following his election in 2019, he turned El Salvador from the murder capital of the world into one of the region's safest countries.
The president of El Salvador told American conservatives to "put up a fight" against the "global elites" in order to get their country back.
"The people of El Salvador have woken up, and so can you," Nayib Bukele said in a speech at the biggest annual gathering of conservatives in the US.
Mr Bukele - who calls himself the world's coolest dictator - was re-elected for a second term this month.
His popularity soared after he cracked down on crime and gangs.
Following his election in 2019, he turned El Salvador from the murder capital of the world into one of the region's safest countries.
But despite his popularity, Mr Bukele remains a controversial figure. Human rights groups say that thousands have been arbitrarily jailed during his anti-gang drive.
He was speaking at Thursday's headline event for the annual Conservative Political Action Conference (CPAC), hosted by the American Conservative Union, a few miles from Washington DC.
The gathering is one of the leading events on the conservative political calendar, and has been transformed in recent years into a heavily pro-Donald Trump affair, a reflection of his takeover of the Republican Party.
The auditorium greeted Mr Bukele with a standing ovation, cheers and shouts of "I love you" as he took to the stage.
The 42-year-old has found a fan base among some American conservatives, who are impressed by his harsh criminal justice policies, while others like him for his stance on cryptocurrency, after he allowed bitcoin to be used as legal tender.
Mr Bukele told the conference that the next US president have the will and courage to do "whatever it takes" to overcome the "dark forces" that he said were trying to control the US.
He received loud applause for when he attacked institutions including what he called "corrupt judges" and fake news in both his country and the US.
He also repeatedly cast an undefined group of "global elites" as an oppressive enemy with power over the media and politics.
"The people of El Salvador have woken up, and so can you," he said. "The global elites, they hate our success and they fear yours."
He said many of the US's big cities were "in decline" and had become "places where crime and drugs have become the daily norm."
"How many young people have you lost on the streets of Philadelphia or San Francisco to fentanyl?" he said. "Can you imagine how we will be in the next five, 10, 15 years?"
He urged the enthusiastic audience: "Put up a fight because in the end it will be worth it. You will have your country back."
Mr Bukele, a former mayor of the capital, San Salvador, first won power in 2019 on a pledge to create a "new era" for El Salvador, take on gang violence and corruption and foster better relations with the US.
His government carried out sweeping arrests of anyone suspected of being involved in gang activity during his first term in office.
An estimated 75,000 people have been arrested under emergency measures that have been repeatedly extended, alarming human rights groups.
Amnesty International recently criticised the "gradual replacement of gang violence with state violence" in the country.
Mr Bukele's re-election was itself controversial. Under the constitution, he was banned from standing for a second consecutive term.
But in 2021 the constitutional court - which is dominated by his supporters - allowed a president to run again, provided he or she stands aside in the period before a second term.
Mr Bukele nominally stepped down as president several weeks ago to fulfil that requirement. He will be sworn in in June.
Other speakers at the conservative conference this week include Nigel Farage, the president of Argentina, and Mr Trump himself on Saturday.