MacAskill last week released Abdel Basset al-Megrahi, the lone person convicted for the 1988 attack over Lockerbie, Scotland, to Libya on compassionate grounds. Megrahi suffers from terminal cancer and is expected to die within months.
MacAskill told lawmakers Monday that his decision was his and his alone, adding it was in line with the Scottish characteristic of humanity, Sky News reports.
"The perpetration of an atrocity and outrage cannot and should not be a basis for losing sight of who we are, the values we seek to uphold, and the faith and beliefs by which we seek to live," he said.
He added he had asked for the views of the British government, but said "they declined" to offer "representations or provide information."
The decision to release Megrahi was met with sweeping condemnation from Western nations, who note the compassionate grounds were in contradiction to the principles of justice.
"Your action in releasing Megrahi is as inexplicable as it is detrimental to the cause of justice," said FBI Director Robert Mueller in a letter to MacAskill.
Mueller went on to say the decision "gives comfort to terrorists" who see their fate in the hands of a single authority, not the perception of a jury.
"Where, I ask, is the justice?" asks Mueller.