Gig company stocks were hammered by the news, with Uber (UBER.N), Lyft (LYFT.O) and DoorDash (DASH.N) all falling at least 10%.
The proposal would require that workers be considered employees, entitled to more benefits and legal protections than contractors, when they are "economically dependent" on a company.
Millions of Americans are working "gig" jobs and this labor has become vital to some transportation, restaurant, construction, health care and other industries.
"Misclassification deprives workers of their federal labor protections, including their right to be paid their full, legally earned wages," Walsh said.
Seth Harris, President Joe Biden's former top labor adviser, said the rule will not directly impact how courts determine whether workers are employees or independent contractors.