MetLife is among the largest global providers of insurance, annuities, and employee benefit programs, with around 90 million customers in over 60 countries.

[9] Through its subsidiaries and affiliates, MetLife holds leading market positions in the United States, Japan, Latin America, Asia's Pacific region, Europe, and the Middle East.

The company insured Civil War sailors and soldiers against disabilities due to wartime wounds, accidents, and sickness.

[17][18] A severe business depression that began with the Panic of 1873 forced the company to contract, until it reached its lowest point in the late 1870s.

[17][19] In 1890, the Metropolitan Life Insurance Company Building was commissioned to serve as MetLife's home office on 23rd Street in Manhattan.

A clock tower was commissioned adjacent to the home office in 1907, and when completed two years later, the building was the world's tallest until 1913.

[20] The home office complex, which came to include the later art deco Metropolitan Life North Building, remained the company's headquarters until 2005.

[22] During the 1930s, it also began to diversify its portfolio by reducing the percentage of individual mortgages in favor of public utility bonds, investments in government securities, and loans for commercial real estate.

[22] During the post-war era, the company expanded its suburban presence, decentralized operations, and refocused its career agency system to serve all market segments.

[25] The de-mutualization process allowed MetLife to enter unrelated insurance businesses and increase executive compensation.

[26] MetLife was accused of breaching federal securities laws by misrepresenting and omitting information in materials given to policyholders during this process, resulting in years of litigation ending with a $50 million settlement in 2009.

[56] In 2015, MetLife was ranked as number one on Fortune magazine's list of World's Most Admired Companies in the Insurance: Life and Health category.

[62] In the summer of 2017, MetLife plans to add a third office building of 255,000 square feet at its Cary, North Carolina Global Technology Campus, giving the company a total of 655,000 square feet at a location which has over 1,000 employees in such areas as engineering, software and technology.

[63] In 2012, MetLife failed the Federal Reserve's (the Fed's) Comprehensive Capital Analysis and Review stress test, intended to predict the potential failure of the company in a recession.

To escape that level of regulation, MetLife announced the sale of its banking unit to GE Capital.

[65][66] On November 2, 2012, MetLife said it was selling its US$70,000,000,000 mortgage servicing business to JPMorgan Chase for an undisclosed amount.

In September 2014, the United States government observed the 2010 Dodd-Frank financial reform law by proposing the application of an official label to MetLife as "systemically important" to the American economy.

[68] If implemented, MetLife would be subject to different sets of rules and regulations, with increased oversight from the Federal Reserve.

[72] On August 7, 2012, it was announced that MetLife will pay $3.2 million in fines after the Federal Reserve charged it used unsafe and unsound practices in handling its mortgage servicing and foreclosure operations.

[73] In 2014, MetLife paid $23 million to settle multiple lawsuits over junk fax operations used to generate leads for life insurance sales.

[81][82] Plans include MetLife's Preferred Dentist Program (PPO) and the SafeGuard DHMO (available for both individuals and employees in CA, FL, TX, NJ and NY.).

[102] Collectively these companies offer personal lines property and casualty insurance policies in all 50 states and the District of Columbia.

[107] The company also provides retirement plans and other financial services to healthcare, education, and not-for-profit organizations.

[111] As of May 2019, MetLife's chief executive officer was Michel A. Khalaf and its non-executive chairman of the board was Glenn Hubbard.

[126] Metlife in partnership with Tishman Realty & Construction co-owns the Walt Disney World Swan and Dolphin resort in Lake Buena Vista, Florida.

[127] Outside of the United States, MetLife operates in Latin America, Europe, Asia's Pacific region, and the Middle East, with leading market positions in Mexico, Japan, South Korea, Bangladesh and Chile.

This decision resulted from the company's sale of its life insurance business to concentrate on corporate clients.

This data followed patients for 18 years (1954–1972) and was collected from 25 life insurance companies in Canada and the United States, representing 4.2 million people.

The ‘’’Metropolitan Tables’’’ included ‘’small’’, ‘’medium’’ and ‘’large’’ frames, based on elbow-girth measured using calipers, as the elbows do not develop adipose tissue.

This led to a formula to calculate the ideal weight used by bariatric surgeons, but it had lost considerable accuracy by 2007, again due to improvements in medical care and in public health.