No, for purposes of calculating the earned income credit, child support is not considered earned income.

Examples of items that are not earned income include interest and dividends, pensions
and annuities, social security and railroad retirement benefits (including disability
benefits), alimony and child support, welfare benefits, workers’ compensation benefits,
unemployment compensation (insurance), nontaxable foster care payments, and
veterans’ benefits, including VA rehabilitation payments. Do not include any of these items in your earned income