Better understanding and management of carbon (C) footprint is an important issue in sustainable food production as it influences climate change. Data from a 19-yr (1992-2010) field experiment were used to determine the effects of N fertilizer rates and crop rotations on i) corn grain yield, ii) total greenhouse gas (GHG) emissions on a per ha basis (kg CO2eq ha-1), and iii) C footprint (kg CO2eq kg-1 grain). On average, continuous corn with well fertilized treatment (200 kg N ha-1) produced 8.1 Mg ha-1 of grain yield, similar to rotational corn with soybean (8.0 Mg ha-1) or lower than corn following alfalfa or red clover (8.9 Mg ha-1), both received 100 kg N ha-1 in the corn year. Continuous corn production had an average of annual total emission of 3440 kg CO2eq ha-1 and C footprints of 0.45 CO2e kg-1 of grain. The annual total emission was 40% less and C footprint 30-44% less for rotational corn than the well fertilized continuous corn. Our results suggest that excessive use of N fertilizer is the main driver of GHG emissions and C footprints and corn-legume crop rotation not only reduces fertilizer consumption, and improves productivity, it also reduces the C footprint.