Nita M. Lowey, a liberal New York Democrat who won a seat in Congress in her early 50s and rose over 16 terms to one of the top positions on Capitol Hill as the first female chair of the House Appropriations Committee, died March 15 at her home in Harrison, New York. She was 87.

The cause was complications from metastatic breast cancer, her family announced.

Ms. Lowey was widely regarded as a workhorse legislator — energetic and unflashy — and became known especially for her work on women’s issues, such as increased funding for breast cancer research.

She sponsored more than 500 pieces of legislation and co-sponsored thousands more, with more than 400 becoming law, often by dint of her seniority and leadership positions. Many of her successful bills were in the areas of health and social welfare; one mandated clear labeling for food allergens and was enacted with bipartisan support after four years of efforts by Ms. Lowey.

Ms. Lowey also served on the Select Committee on Homeland Security and helped New York obtain more than $20 billion for recovery efforts after the Sept. 11, 2001, terrorist attacks.

Her most notable position was on the Appropriations Committee, which sets priorities in spending legislation. She joined in 1993, became the ranking Democrat in 2013 and, after her party regained control of the House in 2019, was the first woman elevated to chair the committee.

Her position “was a great personal accomplishment and indicates the rise of women in the House,” said Ross K. Baker, a political scientist and expert on Congress based at Rutgers University. But, he said, her power also stemmed from being a “loyal lieutenant” to Speaker Nancy Pelosi (D-California).

Pelosi once called Ms. Lowey a “master legislator” who “has earned the respect of all our colleagues as a leader who is both gracious and tenacious; who seeks always to find common ground where she can and stands her ground where she can’t.”

Ms. Lowey was drawn to politics from an early age, participating in student activism during high school and college in the 1950s, and entered government service after her three children were mostly through school.

From 1975 to 1987, she worked in the New York secretary of state’s office, focusing on issues related to child care, housing and the elderly. In 1986, she helped organize the New York State Association of Women Officeholders to train women to run for office. She remembered asking herself one day, “Why not me?”

Starting in 1989, Ms. Lowey represented a district that included part of wealthy Westchester County, north of New York City, and portions of the Bronx and Queens.

In 1991, she was among seven Democratic congresswomen who marched to the Senate to demand consideration of sexual harassment allegations made by Anita Hill against U.S. Supreme Court nominee Clarence Thomas.

Hill, a law professor, alleged that Thomas, a federal judge, had harassed her several years earlier, when she worked for him at the Education Department and at the Equal Employment Opportunity Commission. Thomas and his supporters claimed that he was the victim of a smear campaign.

As the congresswomen reached the Senate, Ms. Lowey said, female staff members stepped out of their offices cheering, “Right on!” But when Ms. Lowey and her colleagues reached the room where Democratic senators were holding a regular caucus meeting, they knocked several times and were rebuffed.

“They did not let us in. They were so rude,” Ms. Lowey recalled to The Washington Post years later.

Senate Majority Leader George Mitchell of Maine met with the women in his office and, later that day, the Senate agreed to delay the vote on Thomas until Hill’s allegations could be investigated. The chairman of the Senate Judiciary Committee, Joe Biden (D-Delaware), said at the time, “The nominee has the right to be confronted by his accuser.” Thomas said he welcomed the delay to “clear my name.”

A week later, after contentious hearings in which Hill testified and Thomas rebutted her accusations and called the scrutiny a “high-tech lynching,” Thomas was confirmed, 52 to 48.

The anger and frustration that spilled out during the hearing was credited, in part, with propelling a record number of women to Congress and other public offices in 1992 in what became known as the “Year of the Woman.”

During the second half of President Donald Trump’s first administration, Ms. Lowey was a key figure in talks to end a government shutdown and to block funding for Trump’s border wall.

“Smart border security is not overly reliant on physical barriers, and they’re not cost-effective compared to better technology and more personnel,” she said at the time, although she declined to rule out border barriers of any kind.

Nita Sue Melnikoff was born in the Bronx on July 5, 1937, and grew up in what she described as a middle-class Jewish family. Her father was a certified public accountant, and her mother was a homemaker involved in community affairs.

She went to the Bronx High School of Science, a prestigious public school where she was senior class president, and to Mount Holyoke College, the women’s college in South Hadley, Massachusetts.

At Mount Holyoke, where she received a bachelor’s degree in political science in 1959, she was president of the campus Jewish organization, raised money for the American Red Cross and Community Chest and had an internship with the Democratic Senatorial Campaign Committee, working with Sen. Hubert H. Humphrey of Minnesota and others.

In 1961, she married Stephen Lowey, a lawyer. In addition to her husband, survivors include three children, Dana, Jackie and Douglas; and eight grandchildren.

“I did not run for office when my children were very young,” Ms. Lowey told the New York Post, “because I would have found it very difficult to keep the late nights and travel frequently. You can’t do everything at the same time. You have to establish priorities.”

In 1988, Ms. Lowey won a three-way primary and then a tough election against conservative Republican incumbent Joseph DioGuardi. After that, she was never seriously challenged until 2020, when Mondaire Jones, a Democrat and a lawyer, won the seat after Ms. Lowey decided to retire.

Ms. Lowey pierced a significant glass ceiling in 2001 when she was named the first woman to chair the Democratic Congressional Campaign Committee. Campaign chairs are often chosen based on the wealth of their constituents, said Baker, the political scientist, and Ms. Lowey’s district included many in Wall Street finance. “It’s a big responsibility,” Baker said, and Ms. Lowey “did a good job recruiting candidates” to run for Congress nationwide.

When Sen. Daniel Patrick Moynihan (D-New York) announced that he would not seek reelection in 2000, Ms. Lowey signaled strong interest in succeeding him. However, after first lady Hillary Clinton declared her intent to run for the same open seat, Ms. Lowey backed out of contention and threw her support to Clinton, who went on to hold the seat until running unsuccessfully for president in 2008.

An earnest, low-key legislator, Ms. Lowey seldom generated headlines, but she drew wide attention twice at congressional hearings — first in 1995 and again 10 years later — when she operated hand puppets of the “Sesame Street” characters Bert and Ernie to protest severe budget cuts at the Corporation for Public Broadcasting.

“When the right wing launched an all-out assault on public television, I invited ‘Sesame Street’ characters Bert and Ernie to help me plead their case before the Appropriations Committee,” she said in 2005. “History repeats itself. The majority is again trying to pull the plug on public television and radio, and Bert and Ernie have returned. … I believe we can repeat the rest of this 10-year-old fight, and save PBS again.”

Both times, Bert and Ernie, and Ms. Lowey, prevailed.