Cabantac is a Bar topnotcher with a Masters degree in Business Administration. He served as a tax specialist at the National Tax Research Center and assisted in the crafting of the value-added tax in 1988. He is also the former first vice president of the Philippine National Bank and undersecretary for legal at the Department of Environment and Natural Resources.
He was also elected as council member at the United Nation’s Global Environmental Facility as well as vice president of the Montreal Protocol.