Speaking in Parliament on Tuesday, the British official also said he supports strengthening EU agencies and enforcement of EU anti-terror policies by member states.
King, who was addressing the committee on civil liberties, justice and home affairs, said the response to the Paris and Brussels attacks was being used as a "model" for any future terrorists atrocities.
He said, "In future, whenever an attack happens, victims must be able to receive immediate and targeted help. This will mark a step change in ensuring that those most affected are dealt with."
The Commissioner told the meeting that the terror threat facing Europe was "still very present and indiscriminate, but we can make a difference."
King, who took up his post earlier this year, cited three legislative proposals currently awaiting approval as examples, including the Schengen border code which was, he said, designed to address the issue of foreign fighters returning to member states, and the counter terrorism directive.
Another proposal is the firearms directive which, he told the meeting, will help ensure that the "most dangerous firearms are not too easily available."
King also said it was important to "invest in our resilience" and said he was impressed by the quality of work undertaken by EU agencies such as Europol and Eurojust in the fight against terror.
"I aim to make it my business to champion and support these agencies. Another key element of my mandate is to ensure that any counter terrorism measures agreed at EU level are correctly and fully enforced by member states."
He added, "We have to squeeze the space in which terrorists can operate and to make it harder for them to finance themselves.
"More efforts are needed also to tackle the root causes of terrorism and radicalisation although these will not produce overnight results."
He told members, "I want to assure everyone that I am committed to a comprehensive review of the EU's counter terror policies.
"My goal is to have a first set of conclusions ready in the first half of next year."