Protestors threw Molotov cocktails and bottles at riot police, who responded with tear gas and pepper spray.
Protestors are angry over new austerity measures that would ensure Greece continues receiving emergency loans that have kept it afloat. Those measures call for $11.5 billion in cutbacks. The country's international lenders are demanding fiscal reforms before they make any more rescue payouts.
The strike closed schools and disrupted flights and many services, including shops, gas stations and tourists sites. Hospitals were functioning on emergency staff.
Shopkeepers, teachers, customs workers and car mechanics were among those taking part in the march in central Athens. It's the first large-scale walk-out since the country's coalition government was formed in June.
The Associated Press contributed to this report.