He told the Daily Telegraph: "I'm proud he took that action and believe me he thinks things through.
"He is not a guy who gets intimidated. I can tell you he is tough and he won't be pushed around. The cards will shake out the way they do but he's tough.
"If there was anything that Syria did, it was to validate the fact that there is no Russia tie."
Eric, whose wife is pregnant with their first child, denounced those behind the atack as "savages" saying he was 'glad' his father bombed the country, Donald Trump, who was previously strongly opposed to a US intervention in Syria, said the US had to act after the Syrian dictator launched the 'horrible chemical weapons attack' on innocent civilians.
"Even beautiful babies were cruelly murdered in this very barbaric attack," he said. "It was a slow and brutal death for so many."
Eric said his father was "deeply affected" by the nerve gas attack, adding that his sister Ivanka had also been appalled by the atrocity.
"Ivanka is a mother of three kids and she has influence," he said. "I'm sure she said 'listen, this is horrible stuff.' My father will act in times like that."
Pentagon officials said that the airfield was being used to store chemical weapons and was a base for Syrian air forces - including the aircraft that conducted the chemical weapons attack.
Syria's state agency SANA claimed that the missiles killed nine civilians, including four children. There were reports nine Syrian jets were destroyed.
The Pentagon has released dramatic footage of its missiles being launched from USS Ross, an Arleigh Burke-class destroyer, targeting the Syrian base.
However, Assad's ally Russia were infuriated by the move.
Russian President Vladimir Putin denounced the strike as an "act of aggression against a UN member" and suspended a deal to avoid mid-air clashes with American fighter jets over the war-torn country.
The Kremlin's propaganda machine clicked into hear claiming the strikes had "extremely low" military effectiveness and that just 23 of 59 cruise missiles reached the air base, destroying six Syrian jets but leaving the runway intact.
Syrian Army officials called the US airstrike a act of "blatant aggression", saying it had made America 'a partner' of ISIS, the ex-Nusra Front and other "terrorist organisations".
The US used a special military-to-military hotline to warn Russia it was launching an airstrike on a Syrian air base about 30 minutes in advance - but the Trump administration did not ask Moscow for permission.
It is likely Russia alerted the Syrians about the incoming strikes but this has not been confirmed.
Eric, 33, who has taken over the running of his father's property empire said his father was committed to building the world's biggest peacetime military force, adding that Donald believed in Ronald Reagan's peace through strength belief.
He added that his father would not be intimidated by Putin's threats of war over Syria.
"He is not a guy who gets intimidated," he warned, "I can tell you he is tough and he won't be pushed around. The cards will shake out the way they do but he's tough."
