Khan was found guilty of two conspiracy counts and two counts of providing material support to terrorists.
"Despite being an Imam, or spiritual leader, Hafiz Khan was by no means a man of peace. Instead, he acted with others to support terrorists to further acts of murder, kidnapping and maiming," Wifredo Ferrer, US Attorney for the Southern District of Florida, said in a statement.
But for law enforcement intervention, these defendants would have continued to transfer funds to Pakistan to finance the Pakistani Taliban, including its purchase of guns, he said after the jury gave its verdict following two months of trial.
"Today, terrorists have lost another funding source to use against innocent people and US interests," said Special Agent in Charge Michael B Steinbach.
"We will not allow this country to be used as a base for funding terrorists. Individuals such as Hafiz Muhammed Sher Ali Khan, who support terror, represent a threat to our safety and provide an example of why the FBI's number one priority is counterterrorism," he said.
According to the evidence, Khan, with the help of persons in South Florida and Pakistan, sent money and other material support to Taliban contacts and sympathisers overseas.
Khan sought to aid the Taliban's fight against the Pakistani government and its perceived allies, including the US, by supporting acts of murder, kidnapping and maiming in Pakistan and elsewhere, in order to establish Sharia.
Khan transferred money from the US to Taliban supporters in Pakistan, primarily using bank accounts and wire transfer services in the United States and Pakistan.
These funds were intended to purchase guns for the Pakistani Taliban, to sustain militants and their families and generally to promote the Pakistani Taliban's cause, the department of justice said in a statement.
Khan also solicited and collected money in the US for that purpose, taking great care to conceal his activities, it added.
In one recorded conversation introduced as evidence, Khan stated that money cannot be sent openly to the Taliban, but must instead be sent covertly through its supporters.
Khan also used a madrassa he founded in Pakistan (where he was born) to provide shelter and other support to Pakistani Taliban militants.
In another recorded conversation, Khan claimed children from his madrassa have gone to train to kill Americans in neighboring Afghanistan, the justice department said.