Springfield was founded in 1636 by English Puritan William Pynchon as "Agawam Plantation" under the administration of the Connecticut Colony. In 1641 it was renamed after Pynchon's hometown of Springfield, Essex, England, following incidents, including trade disputes as well as Captain John Mason's hostilities toward native tribes, which precipitated the settlement's joining the Massachusetts Bay Colony. During its early existence, Springfield flourished both as an agricultural settlement and as a trading post, although its prosperity waned dramatically during (and after) King Philip's War in 1675, when natives laid siege to it and burned it to the ground as part of the ongoing campaign. During that attack, three-quarters of the original settlement was burned to the ground, with many of Springfield's residents survived by taking refuge in John Pynchon's brick house, the "Old Fort", the first such house to be built in the Connecticut River Valley. Out of the siege, Miles Morgan and his sons were lauded as heroes; as one of the few homesteads to survive the attack, alerting troops in Hadley, as well as Toto, often referred to as the "Windsor Indian" who, running 20 miles from Windsor, Connecticut to the settlement, was able to give advance warning of the attack.

The original settlement—today's downtown Springfield—was located atop bluffs at the confluence of four rivers, at the nexus of trade routes to Boston, Albany, New York City, and Montreal, and with some of the northeastern United States' most fertile soil. In 1777, Springfield's location at numerous crossroads led George Washington and Henry Knox to establish the United States' National Armory at Springfield, which produced the first American musket in 1794, and later the famous Springfield rifle. From 1777 until its closing during the Vietnam War, the Springfield Armory attracted skilled laborers to Springfield, making it the United States' longtime center for precision manufacturing. The near-capture of the armory during Shays' Rebellion of 1787 led directly to the formation of the U.S. Constitutional Convention.

During the 19th and 20th centuries, Springfielders produced many innovations, including the first American-English dictionary (1805, Merriam-Webster); the first use of interchangeable parts and the assembly line in manufacturing (1819, Thomas Blanchard); the first American horseless car (1825, Thomas Blanchard); the mass production of vulcanized rubber (1844, Charles Goodyear); the first American gasoline-powered car (1893, Duryea Brothers); the first successful motorcycle company (1901, "Indian"); one of America's first commercial radio stations (1921, WBZ, broadcast from the Hotel Kimball); and most famously, the world's second-most-popular sport, basketball (1891, Dr. James Naismith). Springfield would play major roles in machine production, initially driven by the arms industry of the Armory, as well as from private companies such as Smith & Wesson, established by Horace Smith and Daniel B. Wesson. Similarly, the industrial economy led Thomas and Charles Wason to establish the Wason Manufacturing Company, which produced the first manufactured sleeping car. The largest railcar works in New England, Wason produced 100 cars a day at its peak; the company was eventually was purchased by Brill in 1907 and closed during the Depression in 1937. Among numerous other industries, during the first half of the 20th century Springfield also produced brass goods, chemicals, clothing and knit goods, paper goods, watches, boilers, engines, manufacturing machinery, silverware, jewelry, skates, carriages, buttons, needles, toys, and printed books and magazines.

Springfield underwent a protracted decline during the second half of the 20th century, due largely to the decommissioning of the Springfield Armory in 1969; poor city planning decisions, such as the location of the elevated I-91 along the city's Connecticut River front; and overall decline of industry throughout the northeastern United States. During the 1980s and 1990s, Springfield developed a national reputation for crime, political corruption, and cronyism. During the early 21st century, Springfield saw long-term revitalization projects and several large projects, including the $1 billion New Haven–Hartford–Springfield intercity rail;a $1 billion MGM casino.

According to the 2010 Census, Springfield had a population of 153,060, of which 72,573 (47.4%) were male and 80,487 (52.6%) were female. 73.0% of the population were over 18 years old, and 10.9% were over 65 years old; the median age was 32.2 years. The median age for males was 30.2 years and 34.1 years for females.

According to the 2010 Census, there were 61,706 housing units in Springfield, of which 56,752 were occupied. This was the highest average of home occupancy among the four distinct Western New England metropolises (the other three being Hartford, New Haven, and Bridgeport, Connecticut). Also as of 2010, Springfield features the highest average homeowner occupancy ratio among the four Western New England metropolises at 50%—73,232 Springfielders live in owner-occupied units, versus 74,111 in rental units. By comparison, as of the 2010 Census, New Haven features an owner occupancy rate of 31%; Hartford of 26%; and Bridgeport of 43%.

In terms of race and ethnicity, Springfield is 51.8% White, 22.3% Black or African American, 0.6% American Indian and Alaska Native, 2.4% Asian (1.2% Vietnamese, 0.3% Chinese, 0.2% Indian, 0.1% Cambodian, 0.1% Filipino, 0.1% Korean, 0.1% Pakistani, 0.1% Laotian), 0.1% Native Hawaiian and Other Pacific Islander, 18.0% from Some Other Race, and 4.7% from Two or More Races (1.5% White and Black or African American; 1.0% White and Some Other Race). Hispanics and Latinos of any race made up 38.8% of the population (33.2% Puerto Rican, 1.7% Dominican, 1.0% Mexican, 0.5% Guatemalan, 0.3% Cuban, 0.2% Colombian, 0.2% Spanish, 0.2% Salvadoran, 0.1% Peruvian, 0.1% Ecuadorian, 0.1% Panamanian, 0.1% Costa Rican, 0.1% Honduran).Non-Hispanic Whites were 36.7% of the population in 2010, down from 84.1% in 1970.

Data is from the 2009–2013 American Community Survey 5-Year Estimates.

Notable musical artists include: