"Years of previous attempts at changing Assad's behavior have all failed and failed very dramatically," said Trump.
Assad, 51, has been in power in Syria for nearly two decades and has been labeled by many a brutal dictator who attempts to crush any rebellion against his authority.
He was born September 11, 1965 to Anisa Makhlouf and Hafez al-Assad, a Syrian politician who rose to the presidency in 1971 and served for nearly 30 years. Before he succeeded his father as president, Assad had been an ophthalmologist.
In 1994, Assad received news that his older brother Bassel al-Assad, who was a potential successor to his father, was killed in an automobile accident and he returned home to Syria.
Following his brother's death, Assad was groomed to succeed his father, receiving military training in the mid-1990s and taking on roles in the government. In the late 1990s, Assad was charged with leading Syria's relationship with neighbor Lebanon
Upon his father's death in 2000, Assad -- who had risen to the rank of colonel in the Syrian army -- had already consolidated support in the military and the Baath political party, according to a 2015 BBC report, becoming the commander and secretary general of the two, respectively.
The Syrian Constitution was then amended to lower the minimum age to assume the presidency to 34, Assad’s age at the time.
In July 2000, Assad was voted to a seven-year term as president winning 97 percent support in an election in which he was the only candidate. Assad was elected to a second term in 2007 and a third term in 2014.
The protests in the months that followed, which called for greater reforms and President Assad to step down from power, became increasingly violent as there were reports of security forces opening fire. In December 2011, the U.N. had estimated that since March more than 4,000 people, including children, had been killed as a result of the military crackdown on protests.
Sitting down for a 2011 interview with ABC News, Assad denied he ordered the crackdown.
He responded to the label he was increasingly receiving from the world outside Syria.
"What's important [is] how the Syrian people look at you, not how you look at yourself," Assad said, adding that public opinion of him outside Syria doesn’t matter.
"When I don't have the public support," Assad said. "When I don't represent the Syrian interests and values."