European settlement in the Arlington area dates back at least to the 1840s. After the May 24, 1841 battle between Texas General Edward H. Tarrant and Native Americans of the Village Creek settlement, a trading post was established at Marrow Bone Spring in present-day Arlington (historical marker at 32°42.136′N 97°6.772′W / 32.702267°N 97.112867°W / 32.702267; -97.112867). The rich soil of the area attracted farmers, and several agriculture-related businesses were well established by the late nineteenth century.

Arlington was founded in 1876 along the Texas and Pacific Railway. The city was named after General Robert E. Lee's Arlington House in Arlington County, Virginia. Arlington grew as a cotton-ginning and farming center, and incorporated on April 21, 1884. The city could boast of water, electricity, natural gas, and telephone services by 1910, along with a public school system.

From 1892 until 1951, a mineral well drilled exactly in the middle of downtown Arlington, Texas, was a key reason to visit the town. The water was part of the city's brand, also serving as a meeting point for everything from prohibition to the right of women to vote. The well has been paved over.

Life in 1920s–1930s Arlington was bustling with controversy and entertainment. In the early 1920s, a tea room known as "Top O' Hill Terrace" opened up along the now-defunct Bankhead Highway to serve dinner and tea to guests traveling through Dallas and Fort Worth. Ownership changed in the late 1920s and shortly thereafter the facilities were secretly converted into casinos and a speakeasy. Known by historians as "Vegas before Vegas," escape tunnels and secret rooms were constructed to hide the illegal gambling during police raids. However, the restaurant portion of the facility still existed as a legitimate business and a front.

By 1925 the city's population was estimated at 3,031—well under the population of Dallas and Fort Worth at the time. In 1929, a horse-racing track called Arlington Downs was constructed by W.T. Waggoner close by to the speakeasy. Gambling was still illegal, but people were making bets regardless. Waggoner and his sons campaigned to make parimutuel betting legal, and in 1933 the state issued its first legal gambling permit to Arlington Downs. The track was immensely profitable at that point, making a daily average of $113,000 before inflation with a daily attendance average of 6,700 people. At the end of the 1937 season, the state legislature repealed their parimutuel gambling laws, and the Downs were sold to commercial developers.

In the 1940s, the Arlington Downs was used as a rodeo and event venue. Top O' Hill Terrace evaded the police until 1947, when famous Texas Ranger M. T. "Lone Wolf" Gonzaullas caught the gambling operation in full-swing and had the place shut down. The 1940s brought World War II to the forefront of the United States, and many families from around Texas moved to Arlington to find jobs. Before World War II, the city's population had grown to over 4,000. The war kick-started a manufacturing revolution in Texas. Arlington was between the biggest aerospace engineering hubs in Texas at the time, Dallas and Fort Worth.

In 1956, the Top O' Hill Terrace property was purchased by the Bible Baptist Seminary and converted into what is now Arlington Baptist University. The underground tunnels and original structures are still standing. In 1958, the Arlington Downs was completely destroyed by commercial developers. All that is left is an original concrete water trough and a Texas historical landmark marker placed in 2016. Large-scale industrialization began in 1954 with the arrival of a General Motors assembly plant. Automotive and aerospace development gave the city one of the nation's greatest population growth rates between 1950 and 1990.

Arlington became one of the "boomburbs", the extremely fast-growing suburbs of the post-World War II era. U.S. Census Bureau population figures for the city date the population boom: 7,692 (1950), 90,229 (1970), 261,721 (1990), 365,438 (2010) and almost 374,000 by 2011.Tom Vandergriff served as mayor from 1951 to 1977 during this period of robust economic development. Six Flags Over Texas opened in Arlington in 1961. In 1972 the Washington Senators baseball team relocated to Arlington and began play as the Texas Rangers and in 2009 the Dallas Cowboys also began to play at the newly constructed Cowboys Stadium, now AT&T Stadium.

In October 2019, Arlington was chosen out of several major U.S. cities to become the permanent home of the $150 million National Medal of Honor Museum. Construction of the museum is set to be completed in 2024.

At the census of 2010, there were 365,438 people, 133,072 households, and 90,099 families residing in the city. The population density was 3,811 people per square mile (1,472/km²). There were 144,805 housing units at an average density of 1,510 per square mile (5,833/km²). The 2011 estimated racial makeup of the city (based on the 2010 census) was 59% White, 18.8% Black or African American, 6.8% Asian, 0.7% Native American, 0.1% Pacific Islander, 11.3% from other races, and 3.3% from two or more races. Hispanic or Latino of any race were 27.4% of the population.

There were 133,072 households, out of which 40% had children under the age of 18 living in them, 48% were married couples living together, 15% had a female householder with no husband present, and 32% were non-families. 25% of all households were made up of individuals, and 5% had someone living alone who was 65 years of age or older. The average household size was 2.7 and the average family size was 3.3.

In the city, the 2010 population was spread out, with 31% under the age of 20, 8% from 20 to 24, 30% from 25 to 44, 23% from 45 to 64, and 8% who were 65 years of age or older. The median age was 32 years. For every 100 females, there were 104 males. For every 100 females age 18 and over, there were 94 males 18 and over.

The median income for a household in the city was estimated to be $50,655 in 2011. Individual males working full-time year-round had a median income of $41,059 versus $35,265 for females. The per capita income for the city was $25,317.

About 16% of Arlington families in general and 31% of female-headed families with no husband present were living below the poverty line. 20% of the Arlington population as a whole, including 28% of individuals under age 18 and 8% of those age 65 or over were living in poverty.

43% of Arlington renters and 28% of homeowners were paying 35% or more of their household income for housing costs in 2011.

During the 2018 American Community Survey estimates, Arlington had a population of 392,462. The racial makeup of the city was 39.1% non-Hispanic white, 22% Black or African American, 0.3% American Indian or Alaska Native, 6.8% Asian American, 0.1% Native Hawaiian or other Pacific Islander, 0.3% from some other race, 2.3% from two or more races, and 29.2% Hispanic or Latino of any race. Approximately 20.8% of the population were foreign-born from 2014 to 2018.