The law was seven years in the making. When Greenlee started the push in 2008, Philadelphia was one of the first cities to consider such a measure. Now 16 cities and three states have similar laws, and President Obama is calling on Congress to pass federal sick-leave legislation.
"The hardworking men and women of our city really can't wait another day, another week, another month to have paid sick leave," Nutter said at the signing ceremony.
Asked if he regretted vetoing similar legislation in 2011 and 2013, Nutter said he never opposed sick leave but could not support the measure during the economic recession.
Councilmen David Oh and Brian J. O'Neill, two of Council's three Republicans, were the only members to vote against the measure.
The business community - the hospitality industry, in particular - had lobbied against the bill, saying it could dissuade companies from moving to Philadelphia or current ones from expanding.
The Greater Philadelphia Chamber of Commerce initially asked that the employee threshold be set at 50, then lowered that request to 15.
"It's never been about paid sick leave for our members," said Joe Grace, the chamber's director of public policy. "It's always been about competitiveness."
Workers will be able to use accrued sick time for their own illnesses or those of family members, or to seek support in dealing with domestic violence or sexual assault. Employees not covered include independent contractors, seasonal workers or those hired for fewer than six months, adjunct professors, interns, government employees, and workers covered by collective-bargaining agreements.
Businesses that already provide sick pay on par with or exceeding the law's requirements need not change their policies. Employers that violate the ordinance will be subject to fines, penalties, and restitution.
Jason McCarthy, 43, a bar-back at Monk's Cafe, attended the signing and said that in his two decades working in restaurants, he had experienced the "self-pity and guilt" of going to work knowing he could get others sick.
"Maybe it's one of those things that now I finally have sick days, I'll never need to use another one," he said, adding that it was comforting to have them.
Also on Thursday, Councilwoman Marian B. Tasco introduced a bill to prohibit future waivers of the city's smoking ban in bars and restaurants.
According to city officials, about 85 establishments have waivers. Council is considering four more requests. Tasco said those four should be the last.
Councilwoman Cindy Bass introduced a bill that would require landlords to provide their building's smoking policy in writing to prospective tenants.