In 1959, Reid married his high school girlfriend, Landra Gould. They have five children: a daughter and four sons. Their eldest son, Rory, was an elected commissioner for Clark County, Nevada, of which he became chairman, and 2010 Democratic nominee in the election for Governor of Nevada. Another son, Josh Reid, unsuccessfully sought municipal office in Cottonwood Heights, Utah. In 2014 financial disclosure reports, Reid reported a net worth of between $2.9 million and $9.3 million. Most of Reid’s net worth was in municipal securities and in land and mineral rights in southern Nevada and Arizona; a blind trust managed the liquid assets of Reid and his wife.

Reid returned to Nevada after law school and served as Henderson city attorney before being elected to the Nevada Assembly for the multi-member fourth district of Clark County in 1968. In 1970, at age 30, Reid was chosen by O’Callaghan as his running mate for Lieutenant Governor of Nevada. Reid and O’Callaghan won their respective races, and Reid served as lieutenant governor from 1971 until 1974, when he ran for the U.S. Senate seat being vacated by Alan Bible. He lost by fewer than 700 votes to former governor Paul Laxalt. In 1975, Reid ran for mayor of Las Vegas and lost to Bill Briare.

Reid was born in Searchlight, Nevada, the third of four sons of the Harry Vincent Reid, a rock miner, and Inez Orena (Jaynes) Reid, a laundress. At the time, Searchlight was a small impoverished town. His father committed suicide in 1972 when he was 58; Harry was 32 years old. His paternal grandmother was an English immigrant from Darlaston, Staffordshire. Reid’s boyhood home was a shack with no indoor toilet, hot water, or telephone.

Reid served as chairman of the Nevada Gaming Commission from 1977 to 1981. When Jack Gordon, La Toya Jackson’s future agent and husband, offered Reid a $12,000 bribe to get approval of new games for casinos, Reid brought in the FBI to tape Gordon’s bribery attempt and arrest him. After FBI agents interrupted the transaction, as prearranged, Reid lost his temper and attempted to choke Gordon, saying “You son of a bitch, you tried to bribe me!” before agents stopped him. Gordon was convicted in 1979 and sentenced to six months in prison. In 1981, Reid’s wife found a bomb attached to the family station wagon; Reid suspected it was placed by Gordon, although this has never been proven in a court of law.

Prior to the 1980 Census, Nevada had only a single at-large member in the United States House of Representatives, but population growth in the 1970s resulted in the state picking up a second district. Reid won the Democratic nomination for the 1st district, based in Las Vegas, in 1982, and easily won the general election. He served two terms in the House, from 1983 to 1987, being reelected in 1984.

In 1986, Reid won the Democratic nomination for the seat of retiring two-term incumbent Republican Senator Paul Laxalt. Reid defeated former at-large Congressman Jim Santini, a Democrat who had turned Republican, in the November election. Reid ran for reelection in 1992 which he won by a double-digit margin. In 1998 he narrowly defeated 1st District Congressman John Ensign in the midst of a statewide Republican sweep. In 2004, Reid won reelection with 61 percent of the vote, defeating Richard Ziser.

Part of Reid’s confrontation with Frank Rosenthal while chair of the Nevada Gaming Commission is reenacted in the 1995 movie Casino. Reid had a role in the movie Traffic (2000), in which he played himself. He appeared, with Senators Sam Brownback and Barack Obama, in the 2007 documentary film Sand and Sorrow, which details the genocide in Sudan.

From 1999 to 2005, Reid served as Senate Democratic Whip, as minority whip from 1999 to 2001, and again from 2003 to 2005. Reid was majority whip from 2001 to 2003, except for a brief period from January to May 2001. From 2001 to 2003, he served as chairman of the Senate Ethics Committee. Reid succeeded Tom Daschle as minority leader in 2005, and became majority leader after the 2006 election until 2015. And was again Minority Leader until his retirement in 2017.

Reid believed that Roe vs. Wade should be overturned, and in 1999, voted against an amendment that supported Roe. He stated that he believed in a restricted right to abortion, stating that “abortions should be legal only when the pregnancy resulted from incest, rape, or when the life of the woman is endangered.” He voted several times to ban the “intact dilation and evacuation”, or “partial-birth abortion” procedure. Reid supported embryonic stem cell research.

Ensign was elected to Nevada’s other Senate seat in 2000. Ensign and Reid had a very good relationship despite their bitter contest in 1998. The two frequently worked together on Nevada issues until Ensign was forced to resign from his Senate seat, due to an ethics scandal.

Reid was elected to the Gaming Hall of Fame in 2001. In 2013, adviser Jim Margolis said of Reid, “He is unique in this city. And you see it in so many different ways. Is he the best TV talking head? No. He’d be the first to tell you that. Should he smile more? Yes. Should he say goodbye on the phone when he’s done talking to you? Probably. But those are things you’d assume are part and parcel of a polished figure in Washington. That is not Harry Reid.”

Reid and his family reside in the Anthem area of Henderson, Nevada. Reid (who was raised agnostic) and his wife (who was born to Jewish immigrant parents and grew up in Henderson) converted to The Church of Jesus Christ of Latter-day Saints while he was a college student. In a 2001 interview he said, “I think it is much easier to be a good member of the Church and a Democrat than a good member of the Church and a Republican.” He went on to say that the Democrats’ emphasis on helping others, as opposed to what he considers Republican dogma to the contrary, is the reason he’s a Democrat. He delivered a speech at Brigham Young University to about 4,000 students on October 9, 2007, in which he expressed his opinion that Democratic values mirror Mormon values. Several Republican Mormons in Utah have contested his faith because of his politics, such as his statements that the church’s backing of California’s Proposition 8 wasted resources.

Reid scored a lifetime conservative rating of 19% from the American Conservative Union (ACU), and a 2008 liberal rating of 70% from the Americans for Democratic Action (ADA). Other independent ratings include a 29% rating in 2003 from NARAL, the abortion rights lobbyists, an 85% rating from Planned Parenthood in 2013, and a “B” rating from the National Rifle Association.

Reid was also criticized for several potentially self-enriching tactics. In 2005, Reid earmarked a spending bill to provide for building a bridge between Nevada and Arizona that would make land he owned more valuable. Reid called funding for construction of a bridge over the Colorado River, among other projects, “incredibly good news for Nevada” in a news release after passage of the 2006 transportation bill. He owned 160 acres (65 ha) of land several miles from the proposed bridge site in Arizona. The bridge could add value to his real estate investment. A year later it was reported that Reid had used campaign donations to pay for $3,300 in Christmas gifts to the staff at the condominium where he resides; federal election law prohibits candidates from using political donations for personal use. Reid’s staff stated that his campaign attorneys had approved this use of the funds, but that Reid would personally reimburse his campaign for the expenses. Citizens United filed a complaint with the Federal Election Commission to investigate the matter.

Reid spearheaded several initiatives while in Congress. In 2006, Reid co-sponsored the “Prevention First Amendment” with Hillary Clinton, which would fund abortion prevention efforts such as giving women broader access to contraception. The bill faced Republican opposition and failed. In January 2007, Reid brought a Senate ethics reform bill to a vote to bar congressional members from accepting gifts, meals, and trips from lobbyists and organizations employing lobbyists, to bar Senators from borrowing corporate jets for travel, and to compel Senators to disclose names of sponsors, or authors, of bills and projects. The bill passed 96–2. In the 111th Congress, Reid shepherded the Patient Protection and Affordable Care Act (PPACA) through the Senate.

In 2006, the National Republican Senatorial Committee attempted to associate Reid with the Jack Abramoff Indian lobbying scandal by pointing out he had “received more than $50,000 from four tribes with gaming interests between 2001 and 2004 after they hired Abramoff”. Reid denied any wrongdoing, and media reported that the Center for Responsive Politics, a non-partisan research group, had produced an analysis showing a general increase in the amount and number of contributions by Indian tribes since the late 1990s.

Reid supported use of force in the Middle East, but in September 2007, called for a drastic change in strategy. In January 1991, Reid voted to authorize the first Gulf War, quoting John F. Kennedy’s 1963 State of the Union speech on the Senate floor, saying “the mere absence of war is not peace.” He also voted in support of the 2003 invasion of Iraq. In March 2007, he voted in favor of “redeploying U.S. troops out of Iraq by March 2008”, and later that year, said, “As long as we follow [President Bush’s] path in Iraq, the war is lost.”

Reid called immigration reform one of his priorities at the 110th Congress. He supports the DREAM Act (Development, Relief and Education for Alien Minors Act), which would give certain high school graduates who had arrived in the U.S. illegally, conditional legal status so they could attend college or enlist in the military. They could then obtain permanent legal residency after completing two years of military service or two years of college. In June 2009, Reid announced his intention to enact a new guest worker program as part of a comprehensive immigration reform bill.

Reid won the Democratic nomination with 75% of the vote in the June 8 primary. He faced a very competitive general election for the Senate in Nevada in 2010. Reid engaged in a $1 million media campaign to “reintroduce himself” to the state’s voters. He defeated Republican challenger Sharron Angle in the November election, 50.3% to 44.6%, despite losing 14 of Nevada’s 17 counties.

Reid apologized on January 9, 2010, for racially tinged comments he had made when Obama was campaigning for president. In private conversations, Reid had remarked that Obama could win the presidency because the country was ready to embrace a black presidential candidate, especially one such as Obama — to whom he referred as being “light-skinned” and “with no Negro dialect, unless he wanted to have one”. These comments had been recently revealed by journalists Mark Halperin and John Heilemann in Game Change, their book about the 2008 United States presidential election. In addition to his public apology, Reid called Obama to apologize; Obama accepted his apology, stating that as far as he was concerned, the book was closed on the incident. RNC Chairman Michael Steele and Senators John Cornyn and Jon Kyl called on Reid to resign his leadership position in the Senate, citing Majority Leader Trent Lott resigning because of a statement relating to race. However, multiple experts said there was virtually no chance of that. DNC Chairman Tim Kaine and Senators Dianne Feinstein and Jack Reed expressed support for Reid and confidence he would retain his leadership position, and another senior Democrat indicated Reid has “produced supportive statements from key African American leaders in the Congress and civil rights community”.

In August 2010, Reid spoke in front of National Council of La Raza: “I don’t know how anyone of Hispanic heritage could be a Republican, OK. Do I need to say more?” The following day, Dr. Manny Alvarez and Republican Senate-candidate Marco Rubio, both of Hispanic descent, spoke out against Reid’s remarks.

In September 2011, Reid’s wife was diagnosed with stage 2 breast cancer. Reid is the co-chairman of the Board of Selectors of Jefferson Awards for Public Service. In April 2015, Reid confirmed former U.S. Senator Larry Pressler as a member of The Church of Jesus Christ of Latter-day Saints.

Regarding same-sex marriage, Reid initially believed that “marriage should be between a man and a woman”, but abandoned that position in favor of same-sex marriage in 2012.

During the summer of 2012, Reid said during an interview with The Huffington Post that he had received information from an unidentified investor in Bain Capital that presumptive Republican presidential nominee Mitt Romney did not pay any taxes for 10 years. The accusation was repeated on the Senate floor by Reid on August 2, 2012. According to CBS News, Romney stated, “Let me also say, categorically, I have paid taxes every year — and a lot of taxes. So Harry is simply wrong.” PolitiFact.com’s Truth-O-Meter rated the accusation as “Pants on Fire!” The Washington Post’s Fact Checker gave it “Four Pinnocchios”. CBS reported that Romney had submitted 23 years of tax returns to the John McCain campaign in 2008, when he was being vetted for the vice presidential nomination. McCain said, “[n]othing in these tax returns showed that he did not pay taxes.” After the election, Reid called the attack “one of the best things I’ve ever done”. He also said, “Romney didn’t win, did he?”

In 2012, Reid cited fellow U.S. Senator Bernie Sanders, who claimed the Koch brothers were “funding think tanks spreading an enormous amount of disinformation about Social Security”. Two years later, in 2014, Reid accused the brothers of having Republicans stall aid to Ukraine by pushing for amendments like a delay of regulation by the IRS of non-profit political advocacy groups to be included in the aid package. Reid “credited his wife, Landra, for likening the Republicans’ Ukrainian stance to a ‘Koch addiction'”.

On May 15, 2013, Reid revealed to reporters that his niece is a lesbian as he spoke about his hope that the Employment Non-Discrimination Act would be signed into law.

A series of investigative reports in the Los Angeles Times suggested that Reid had introduced legislation and imposed pressure on regulatory agencies to advance the business interests of his close friend Harvey Whittemore, a Nevada attorney-lobbyist who contributed heavily to Reid’s campaigns and leadership fund and who employed Reid’s son Leif as his personal attorney. With Reid’s help, Whittemore was able to proceed with construction of a $30 billion planned golf course development, Coyote Springs, a project heavily criticized by environmental groups for reasons including its projected effects on several endangered species. Whittemore served a two-year prison sentence after being found guilty in 2013 of funneling $133,400 in illegal contributions to Reid’s reelection campaign.

In January 2015, Reid suffered severe injuries in an exercise accident. On March 27, 2015, Reid uploaded a video to his YouTube account announcing that he would not seek re-election in November 2016. Reid endorsed New York Senator Chuck Schumer (D) to succeed him as Minority Leader. He was succeeded by former Nevada Attorney General and fellow Democrat Catherine Cortez Masto.

In 2015, Reid received a lifetime achievement award from the League of Conservation Voters, and the following year he was honored by the Conservation Lands Foundation for “historic contributions to conservation.”

On January 1, 2015, Reid was injured while exercising in his home—he said a piece of equipment he was using broke (later “slipped”), causing him to fall. As a result, Reid suffered broken ribs and broken facial bones, and was at risk of permanent vision loss in his right eye. On January 26, 2015, Reid underwent surgery to remove a blood clot from his right eye and repair facial bones. Reid later sued for damages a company he claimed manufactured the device, alleging the device was defective, but in 2019 a jury rejected his claim for lack of evidence.

On January 1, 2017, two days before the end of his term, Reid surpassed Sen. John P. Jones to become the longest-serving Senator from Nevada.

On May 14, 2018, Reid had surgery for pancreatic cancer at Johns Hopkins Cancer Center after a tumor was found on his pancreas during a routine screening. In a January 2019 interview with The New York Times, it was revealed that Reid was confined to a desk at his home and was unable to move without the aid of a walker. Upon his diagnosis, Reid said: “As soon as you discover you have something on your pancreas, you’re dead”. On February 25, 2019, Reid announced that due to early detection and chemotherapy, his cancer is in remission.