Disclosed is a method of hydrotreating a heavy hydrocarbon feedstock using a hydrotreating catalyst having specific properties that make it effective in converting nitrogen, sulfur and micro-carbon residue of a heavy hydrocarbon feedstock. The catalyst comprises a calcined support particle impregnated with a Group 6 metal component (e.g., molybdenum), a nickel component, and a phosphorus component present at concentrations in the catalyst such that the atomic ratio of the Group 6 metal-to nickel metal are within a specified range. The nickel metal acid extractability property of the catalyst is at least 50 percent.