In 1938, Lee Byung-chull (1910–1987) of a large landowning family in the Uiryeong county came to the nearby Daegu city and founded Samsung Sanghoe (삼성상회, 三星商會), a small trading company with forty employees located in Su-dong (now Ingyo-dong). It dealt in groceries produced in and around the city and produced its own noodles. The company prospered and Lee moved its head office to Seoul in 1947. When the Korean War broke out, however, he was forced to leave Seoul and started a sugar refinery in Busannamed Cheil Jedang. After the war, in 1954, Lee founded Cheil Mojik and built the plant in Chimsan-dong, Daegu. It was the largest woolen mill ever in the country and the company took on the aspect of a major company.

Samsung diversified into many areas and Lee sought to help establish Samsung as an industry leader in a wide range of enterprises, moving into businesses such as insurance, securities, and retail. President Park Chung Hee placed great importance on industrialization, and focused his economic development strategy on a handful of large domestic conglomerates, protecting them from competition and assisting them financially.

In 1947, Cho Hong-jai (the Hyosung group’s founder) jointly invested in a new company called Samsung Mulsan Gongsa (삼성물산공사), or the Samsung Trading Corporation, with the Samsung Group founder Lee Byung-chull. The trading firm grew to become the present-day Samsung C&T Corporation. But after some years Cho and Lee separated due to differences in management between them. He wanted to get up to a 30% group share. After settlement, Samsung Group was separated into Samsung Group and Hyosung Group, Hankook Tire, and others.

In the late 1960s, Samsung Group entered into the electronics industry. It formed several electronics-related divisions, such as Samsung Electronics Devices, Samsung Electro-Mechanics, Samsung Corning, and Samsung Semiconductor & Telecommunications, and made the facility in Suwon. Its first product was a black-and-white television set.

In 1980, Samsung acquired the Gumi-based Hanguk Jeonja Tongsin and entered the telecommunications hardware industry. Its early products were switchboards. The facility was developed into the telephone and fax manufacturing systems and became the center of Samsung's mobile phone manufacturing. They have produced over 800 million mobile phones to date. The company grouped them together under Samsung Electronics in the 1980s.

After Lee, the founder's death in 1987, Samsung Group was separated into four business groups—Samsung Group, Shinsegae Group, CJ Group, and the Hansol Group. Shinsegae (discount store, department store) was originally part of Samsung Group, separated in the 1990s from the Samsung Group along with CJ Group (Food/Chemicals/Entertainment/logistics) and the Hansol Group (Paper/Telecom). Today these separated groups are independent and they are not part of or connected to the Samsung Group. One Hansol Group representative said, "Only people ignorant of the laws governing the business world could believe something so absurd", adding, "When Hansol separated from the Samsung Group in 1991, it severed all payment guarantees and share-holding ties with Samsung affiliates." One Hansol Group source asserted, "Hansol, Shinsegae, and CJ have been under independent management since their respective separations from the Samsung Group". One Shinsegae department store executive director said, "Shinsegae has no payment guarantees associated with the Samsung Group".

In 1980s, Samsung Electronics began to invest heavily in research and development, investments that were pivotal in pushing the company to the forefront of the global electronics industry. In 1982, it built a television assembly plant in Portugal; in 1984, a plant in New York; in 1985, a plant in Tokyo; in 1987, a facility in England; and another facility in Austin, Texas, in 1996. As of 2012, Samsung has invested more than US$13 billion in the Austin facility, which operates under the name Samsung Austin Semiconductor. This makes the Austin location the largest foreign investment in Texas and one of the largest single foreign investments in the United States.

Samsung started to rise as an international corporation in the 1990s. Samsung's construction branch was awarded a contract to build one of the two Petronas Towers in Malaysia, Taipei 101 in Taiwan and the Burj Khalifa in United Arab Emirates. In 1993, Lee Kun-hee sold off ten of Samsung Group's subsidiaries, downsized the company, and merged other operations to concentrate on three industries: electronics, engineering, and chemicals. In 1996, the Samsung Group reacquired the Sungkyunkwan University foundation.

Samsung became the largest producer of memory chips in the world in 1992, and is the world's second-largest chipmaker after Intel (see Worldwide Top 20 Semiconductor Market Share Ranking Year by Year).In 1995, it created its first liquid-crystal display screen. Ten years later, Samsung grew to be the world's largest manufacturer of liquid-crystal display panels.Sony, which had not invested in large-size TFT-LCDs, contacted Samsung to cooperate, and, in 2006, S-LCD was established as a joint venture between Samsung and Sony in order to provide a stable supply of LCD panels for both manufacturers. S-LCD was owned by Samsung (50% plus one share) and Sony (50% minus one share) and operates its factories and facilities in Tangjung, South Korea. As of 26 December 2011 it was announced that Samsung had acquired the stake of Sony in this joint venture.

Compared to other major Korean companies, Samsung survived the 1997 Asian financial crisis relatively unharmed. However, Samsung Motor was sold to Renault at a significant loss. As of 2010, Renault Samsung is 80.1 percent owned by Renault and 19.9 percent owned by Samsung. Additionally, Samsung manufactured a range of aircraft from the 1980s to 1990s. The company was founded in 1999 as Korea Aerospace Industries (KAI), the result of merger between then three domestic major aerospace divisions of Samsung Aerospace, Daewoo Heavy Industries, and Hyundai Space and Aircraft Company. However, Samsung still manufactures aircraft engines and gas turbines. 

In 2000, Samsung opened a computer programming laboratory in Warsaw, Poland. Its work began with set-top-box technology before moving into digital TV and smartphones. As of 2011, the Warsaw base is Samsung's most important R&D center in Europe, forecast to be recruiting 400 new-hires per year by the end of 2013.

In 2010, Samsung announced a ten-year growth strategy centered around five businesses. One of these businesses was to be focused on biopharmaceuticals, to which the company has committed ₩2.1 trillion.

In December 2011, Samsung Electronics sold its hard disk drive (HDD) business to Seagate.

In first quarter of 2012, Samsung Electronics became the world's largest mobile phone maker by unit sales, overtaking Nokia, which had been the market leader since 1998.On 21 August's edition of the Austin American-Statesman, Samsung confirmed plans to spend 3 to 4 billion dollars converting half of its Austin chip manufacturing plant to a more profitable chip. The conversion should start in early 2013 with production on line by the end of 2013. On 14 March 2013, Samsung unveiled the Galaxy S4.

On 24 August 2012, nine American jurors ruled that Samsung had to pay Apple$1.05 billion in damages for violating six of its patents on smartphone technology. The award was still less than the $2.5 billion requested by Apple. The decision also ruled that Apple did not violate five Samsung patents cited in the case. Samsung decried the decision saying that the move could harm innovation in the sector. It also followed a South Korean ruling stating that both companies were guilty of infringing on each other's intellectual property. In first trading after the ruling, Samsung shares on the Kospi index fell 7.7%, the largest fall since 24 October 2008, to 1,177,000 Korean won.Apple then sought to ban the sales of eight Samsung phones (Galaxy S 4G, Galaxy S2 AT&T, Galaxy S2 Skyrocket, Galaxy S2 T-Mobile, Galaxy S2 Epic 4G, Galaxy S Showcase, Droid Charge and Galaxy Prevail) in the United States^] which has been denied by the court.

On 4 September 2012, Samsung announced that it plans to examine all of its Chinese suppliers for possible violations of labor policies. The company said it will carry out audits of 250 Chinese companies that are its exclusive suppliers to see if children under the age of 16 are being used in their factories.

In 2013, a New Zealand news outlet reported a number of Samsung washing machines spontaneously catching on fire.The corporation is expected to spend $14 billion on advertising and marketing in 2013, with publicity appearing in TV and cinema ads, on billboards, and at sports and arts events. In November 2013, the corporation was valued at $227 billion.

In May 2014, Samsung announced it will be shutting down its streaming service on 1 July 2014, also meaning the end of the Samsung Music Hub app that typically comes installed on its Android phones.

On 3 September 2014, Samsung announced Gear VR, a virtual reality device in collaboration with Oculus VR and developed for the Galaxy Note 4.

In October 2014, Samsung announced a $14.7 billion investment to build a chip plant in South Korea. Construction will begin next year with production beginning in 2017. The company has not yet decided the type of chips to be produced.

In October 2014, Samsung also announced it would invest $560 million in the construction of a new 700,000 square metre production complex in Vietnam

Samsung plans to launch a new set of services beginning early 2015. The goal of this new suite of business offerings, dubbed Samsung 360 Services, is to become a help desk of sorts for businesses IT departments. The customizable services range from technical support to security solutions for having a Samsung employee embedded in a client's business as an on-site support manager or technology consultant.

On 2 December 2014, Samsung announced it will sell Fiber Optics to U.S. speciality glass manufacturer Corning Inc.