The mayoralty of Michael Bloomberg began on January 1, 2002, when Michael Bloomberg was inaugurated as the 109th mayor of New York City, and ended on December 31, 2013.

Bloomberg was known as a political pragmatist, and for a managerial style that reflected his experience in the private sector. Bloomberg chose to apply a statistical approach to city management, appointing city commissioners based on their expertise and granting them wide autonomy in their decision-making. Breaking with 190 years of tradition, Bloomberg implemented a "bullpen" open plan office, reminiscent of a Wall Street trading floor, in which dozens of aides and managerial staff are seated together in a large chamber. The design was intended to promote accountability and accessibility.D. Eisenberg, "Mike Bloomberg/New York", Time, April 17, 2005. At the end of Bloomberg's three terms, The New York Times said, "New York is once again a thriving, appealing city where [...] the crime rate is down, the transportation system is more efficient, the environment is cleaner."

Elections and re-elections

2001 election

In 2001, the incumbent mayor of New York City, Rudy Giuliani, was ineligible for re-election, as the city limited the mayoralty to two consecutive terms. Several well-known New York City politicians aspired to succeed him. Bloomberg, a lifelong member of the Democratic Party, decided to run for mayor as a member of the Republican Party ticket.

Voting in the primary began on the morning of September 11, 2001. The primary was postponed later that day because of the terrorist attacks on the World Trade Center. In the rescheduled primary, Bloomberg defeated Herman Badillo, a former Congressman, to become the Republican nominee. Meanwhile, the Democratic primary did not produce a first-round winner. After a runoff, the Democratic nomination went to New York City Public Advocate Mark Green.

In the general election, Bloomberg received Giuliani's endorsement. He also had a huge spending advantage. Although New York City's public campaign finance law restricts the size of contributions which a candidate can accept, Bloomberg chose not to use public campaign funds and instead self-financed his campaign. He spent $73 million of his own money on his campaign, outspending Green five to one. One of the major themes of his campaign was that, with the city's economy suffering from the effects of the World Trade Center attacks, it needed a mayor with business experience.

In addition to serving as the Republican nominee, Bloomberg had the ballot line of the Independence Party. Under New York's fusion rules, a candidate can run on more than one party's line and combine all the votes received on all lines. Green, the Democrat, also had the ballot line of the Working Families Party. Bloomberg also created an independent line called Students First whose votes were combined with those on the Independence line. Overall, he won 50 percent to 48 percent.

Bloomberg's election marked the first time in New York City history that two different Republicans had been elected mayor consecutively. New York City has not been won by a Republican in a presidential election since Calvin Coolidge won in 1924. Bloomberg is considered a social liberal: He is pro-choice, favors legalizing same-sex marriage, and is an advocate for stricter gun control laws.

In 2002, Bloomberg delivered bids from New York City to host both the Democratic and Republican nominating conventions for the 2004 presidential campaign. The city won the bid to host the Republican National Convention in 2004. The convention drew thousands of protesters, many of them local residents angry over the Iraq War and other issues. The New York Police Department arrested approximately 1,800 protesters, but most of the cases were later dismissed.

2005 election

Bloomberg was re-elected mayor in November 2005 by a margin of 20 percent, the widest margin ever for a Republican mayor of New York.

Bloomberg had spent $102 million on his campaign by late October 2005. In late 2004 or early 2005, Bloomberg gave the Independence Party of New York $250,000 to fund a phone bank seeking to recruit volunteers for his re-election campaign.

Former Bronx Borough President Fernando Ferrer won the Democratic nomination to oppose Bloomberg in the general election. Thomas Ognibene sought to run against Bloomberg in the Republican Party's primary election. Bloomberg's campaign successfully challenged enough of the signatures Ognibene had submitted to the Board of Elections to prevent Ognibene from appearing on ballots for the Republican primary. Instead, Ognibene ran only on the Conservative Party ticket. Ognibene accused Bloomberg of betraying Republican Party ideals, a feeling echoed by others.

Bloomberg opposed the confirmation of John Roberts as Chief Justice of the United States. Though a Republican at the time, Bloomberg is a staunch supporter of abortion rights and did not believe that Roberts was committed to maintaining Roe v. Wade.

In addition to receiving Republican support, Bloomberg obtained the endorsements of several prominent Democrats: former Democratic Mayor Ed Koch; former Democratic governor Hugh Carey; former Democratic City Council Speaker Peter Vallone, and his son, Councilman Peter Vallone, Jr.; former Democratic Congressman Floyd Flake (who had previously endorsed Bloomberg in 2001), and Brooklyn Borough President Marty Markowitz.

2009 election

On October 2, 2008, Bloomberg announced that he would seek to extend the city's term limits law and run for a third mayoral term in 2009, arguing that a leader of his field was needed during the 2008 financial crisis. "Handling this financial crisis while strengthening essential services ... is a challenge I want to take on," Bloomberg said at a news conference. "So should the City Council vote to amend term limits, I plan to ask New Yorkers to look at my record of independent leadership and then decide if I have earned another term." Bloomberg promised Ronald Lauder, who wrote New York City's term limits in 1993 and spent over 4 million dollars of his own money to enable the maximum years a mayor could serve to eight years, a seat on an influential board; he agreed to stay out of future legality issues and sided with Bloomberg in running for a third term. NYPIRG filed a complaint with the City Conflict of Interest Board. On October 23, 2008, the City Council voted 29–22 in favor of extending the term limit to three consecutive four-year terms, thus allowing Bloomberg to run for office again. After two days of public hearings, Bloomberg signed the bill into law on November 3.

Bloomberg's bid for a third term generated some controversy. Civil libertarians such as former New York Civil Liberties Union Director Norman Siegel and New York Civil Rights Coalition Executive Director Michael Meyers joined with local politicians such as New York State Senator Eric Adams to protest the term limits extension.

Bloomberg's opponent was Democratic and Working Families Party nominee Bill Thompson, who had been New York City Comptroller for the past eight years and before that, President of the New York City Board of Education. Bloomberg defeated Thompson by a vote of 50.6 percent to 46.0 percent.

After the release of Independence Party campaign filings in January 2010, it was reported that Bloomberg had made two $600,000 contributions from his personal account to the Independence Party on October 30 and November 2, 2009. The Independence Party then paid $750,000 of that money to Republican Party political operative John Haggerty Jr.

This prompted an investigation beginning in February 2010 by the office of New York County District Attorney Cyrus Vance, Jr. into possible improprieties. The Independence Party later questioned how Haggerty spent the money, which was to go to poll-watchers. Former New York State Senator Martin Connor contended that because the Bloomberg donations were made to an Independence Party housekeeping account rather than to an account meant for current campaigns, this was a violation of campaign finance laws. Haggerty also spent money from a separate $200,000 donation from Bloomberg on office space. In 2011, Haggerty was convicted of stealing campaign funds from Bloomberg; he admitted his guilt and was sentenced to one and a third to four years in prison.

2013 election endorsements

On September 13, 2013, Bloomberg announced that he would not endorse any of then current candidates to succeed him. On his radio show, he stated, "I don't want to do anything that complicates it for the next mayor. And that's one of the reasons I've decided I'm just not going to make an endorsement in the race." He added, "I want to make sure that person is ready to succeed, to take what we've done and build on that."

Prior to the announcement in an interview in New York magazine, Bloomberg praised the New York Times for its endorsement of Christine Quinn and Joe Lhota, respectively, as their favorite candidates in the Democratic and Republican primaries. Quinn came in third in the Democratic primary and Lhota won the Republican primary.

Earlier in the month, Bloomberg was chastised in the press for his remarks regarding Democratic mayoral candidate Bill de Blasio's campaign methods. Bloomberg said initially in the New York magazine interview that he considered de Blasio's campaign "racist".

Well, no, no, I mean he's making an appeal using his family to gain support. I think it's pretty obvious to anyone watching what he's been doing. I do not think he himself is racist. It's comparable to me pointing out I'm Jewish in attracting the Jewish vote. You tailor messages to your audiences and address issues you think your audience cares about.

Public opinion Throughout 2006 and 2007, Bloomberg had approval ratings consistently above 70%, according to the Quinnipiac University Polling Institute. Differences between Republican, Democratic and independent voters were small. "An effective, straightforward guy who calls it as it is – that's Mayor Bloomberg's most attractive quality, New Yorkers think. And they like his businessman approach to the job," said Quinnipiac polling director Maurice Carroll.

Bloomberg had a 49% approval rating in August 2010 compared to 56% in April. It also stated in August that 47% of Democratic voters expressed approval compared to 55% of Republican voters. Lee Miringoff, director of Marist College's Institute for Public Opinion, remarked that governing during a world economic recession coupled with Bloomberg's stance in support of the Islamic complex near Ground Zero (Bloomberg defended the owner's right to build when few other did) had dampened Bloomberg's polling numbers.

In November 2010, a Public Policy Polling survey of registered voters found that 19% expressed a favorable opinion of Bloomberg, while an 38% plurality expressed a negative view.

Five months before the end of Bloomberg's tenure, a New York Times survey placed his approval rating at 49%, against 40% who disapproved. In a January 2014 Quinnipiac poll, 64 percent of voters called Bloomberg's 12 years as mayor "mainly a success."

Public initiatives

Infrastructure

Technology