Mary Kay Henry, the president of the Service Workers Worldwide Union, one of many nation’s largest and most politically highly effective labor unions, introduced Tuesday that she would step down after 14 years in her place.

Ms. Henry was the primary lady elected to steer the union, which represents practically two million staff like janitors and residential well being aides in each the private and non-private sectors.

Beneath her management, it launched a significant initiative generally known as the Struggle for $15, which sought to arrange fast-food staff and push for a $15 minimal wage. Profitable over skeptics within the ranks, Ms. Henry argued that the union may make positive factors by way of a broad-based marketing campaign that focused the business as a complete slightly than particular person employers.

Labor consultants and business officers cite the marketing campaign as a significant power behind vital minimum-wage will increase in states together with California and New York and cities like Seattle and Chicago. It additionally pushed a recent California law making a council to set a minimal wage within the fast-food business, which can develop into $20 an hour in April, and to suggest new well being and security requirements.

Ruth Milkman, a sociologist of labor on the Graduate Middle of the Metropolis College of New York, mentioned the union beneath Ms. Henry had been “prepared to take possibilities on fairly daring initiatives” and known as the Struggle for $15 an “extraordinary achievement.”

However the marketing campaign has not unionized staff on a big scale and enabled them to barter collective bargaining agreements with their employers.

Ms. Henry’s tenure has coincided with a sequence of legislative and authorized challenges to organized labor, together with state legal guidelines rolling again collective bargaining rights and permitting staff to choose out of once-mandatory union charges, in addition to a landmark Supreme Court docket ruling permitting authorities staff to do the identical.

The union’s membership has stayed practically flat on Ms. Henry’s watch, whereas the general proportion of Individuals represented by unions has declined roughly 15 p.c. However the union misplaced obligatory charges from greater than 200,000 nonmembers, inflicting a major lack of income.

The union will choose Ms. Henry’s successor by way of a vote of delegates at its quadrennial conference in Might.

“I’m able to go the baton,” Ms. Henry, 66, mentioned in an interview. “S.E.I.U. is full of highly effective, dynamic, multiracial leaders of the subsequent technology who’re able to seize this second of employee rebellion.”

The union’s second-ranking official, Secretary-Treasurer April Verrett, mentioned in an interview that she meant to be a candidate for the highest job.

A longtime organizer, Ms. Henry was an government vp when the union’s board selected her to fill out the presidential time period of Andy Stern, who resigned in 2010. She received the primary of three full four-year phrases in 2012.

Ms. Henry’s strategy has invited criticism that the union is just too top-down in its efforts.

The organizer and scholar Jane McAlevey has criticized the Struggle for $15 for being too targeted on what she calls “mobilizing” — that’s, relying closely on knowledgeable workers, consultants and activists to generate consideration and form public opinion — slightly than constructing an in depth, worker-led group.

As S.E.I.U. acquired extra concerned in a union marketing campaign that an affiliate, Employees United, launched at Starbucks in 2021, some Starbucks staff mentioned decision-making and communications had develop into extra centralized.

Within the interview, Ms. Henry rejected the rivalry that the union’s campaigns didn’t prominently contain staff, however mentioned it was necessary to pair ground-level organizing with different methods that pressured employers.

The union has additionally been a power in politics and in coverage debates. Ms. Henry took the highest job shortly after President Barack Obama signed the Inexpensive Care Act, which the union had mobilized to assist go. She threw the union into defending the well being care laws in opposition to Republican makes an attempt to repeal it.

The union’s political bets beneath Ms. Henry haven’t all the time labored out, like its endorsement of Hillary Clinton early within the 2016 presidential marketing campaign cycle. Many members later turned obsessed with her Democratic main rival, Bernie Sanders.

In 2020, the union took a special tack, laying out a coverage agenda that it urged candidates to embrace, which included making it simpler for staff to discount on an industrywide foundation and making massive investments in house care and baby care, together with elevated pay for care staff. Joseph R. Biden Jr. integrated lots of the union’s concepts into his home coverage platform en path to the presidency.

“It’s an instance of how we take inventory and consider management choices, and draw classes and take into consideration what we wish to do in a different way subsequent time,” Ms. Henry mentioned of the change in strategy.

Nonetheless, main house care and baby care measures proposed by Mr. Biden died within the Senate.

Ms. Henry mentioned the union was spending closely on this 12 months’s political elections — a sum prone to exceed $100 million, in line with a union official.

“We wish to end the job,” she mentioned. “We’ve got Senate targets, Home targets, governors, state legislators, metropolis councils — to make all the foremost positive factors we will make.”