The town's name means the territory of Ketter's people, a kindred group whose name has long since otherwise vanished. People have lived on this land for at least 2,700 years. Iron-Age hill forts dotted the surrounding country from around 700 BC. The Romans came in AD 43 and turned the area into one of the three great centres of iron-working in Roman Britain, alongside the Forest of Dean and the Weald of Kent and Sussex. The unwalled Romano-British settlement that grew up here lies under the northern part of the modern town. Around the 5th century the Saxons arrived, leaving an early burial ground of more than a hundred cremation urns near what is now the Warren pub. Then in 889 the Danes conquered most of England outside the Somerset marshes, and Northamptonshire became part of the Danelaw. The English took it back in 917, the Vikings of York took it again in 940, and the English took it back once more in 942. Kettering as a recognisable village probably did not exist until the tenth century, by which point most of the dust had settled.

In 1607 something happened in the villages around Kettering that English history books often skip past, which is a shame because it was one of the last open conflicts between peasantry and gentry in English history. The Tresham family of Newton and Pytchley had been enclosing common land, fencing off ground that local people had farmed and grazed for generations. On 8 June 1607, a pitched battle was fought between landowners' servants and rebels from Kettering, Corby, and especially Weldon, who called themselves Levellers. Local militias refused the gentry's call to arms, perhaps because they were drawn from the same villages as the rebels. Forty to fifty men died on the field. The ringleaders were hanged, drawn, and quartered, the medieval punishment still being meted out for treason in seventeenth-century England. The Newton rebellion is sometimes described as the first popular use of the word Levellers, the name that would become famous during the English Civil War forty years later. It is a moment when ordinary English people drew a line, and were brutally taught they could not.

The modern town is largely a creation of the nineteenth-century boot and shoe industry. Northamptonshire as a whole became famous for footwear, and Kettering's factory owners built grand houses on Headlands and Rockingham Road while their workers occupied the terraced streets nearby. Dolcis, Freeman Hardy and Willis, Frank Wright, Timpsons: these were the names that once meant Kettering. Most have closed or moved production abroad. The Midland Railway arrived in 1857 connecting Kettering to London and Leicester, and by the late nineteenth century the town was also smelting iron and quarrying ore from beds exposed during the railway cuttings. The Glendon quarries operated until 1980. In 1921 a man named Charles Wicksteed opened Britain's second-oldest theme park on the southern edge of town, with a steam-driven roundabout, swings, and a boating lake. Wicksteed Park is still there, drawing 1.25 million visitors a year. The company that built it, Wicksteed Playscapes, is now the world's oldest known playground equipment manufacturer. Some industries last.

Modern Kettering's economy runs on service and distribution rather than shoemaking, thanks to its location at the meeting of the A14, A43, A6003, A509, and A6. Weetabix has its global headquarters here. Aquascutum, the raincoat maker that dressed two world wars of British army officers, opened its first factory in Kettering in 1909. The town's unemployment rate is among the lowest in Britain, with over 80% of adults in full-time work. Kettering Town Football Club plays in the National League North, several leagues below where they have sometimes been, currently at Latimer Park in nearby Burton Latimer after losing their old ground at Rockingham Road in 2011. The 2024 World Snooker Champion Kyren Wilson grew up in Kettering. The BBC sitcom Peep Show situated the head office of Mark Corrigan's employer JLB in Kettering, an in-joke that has lent the town a particular kind of comedic shorthand. None of this hints at the town's stranger landmarks: the Triangular Lodge built in 1597 by the recusant Catholic Sir Thomas Tresham, three sides and three storeys high in defiance of the Protestant authorities who had imprisoned him for his faith, every measurement coded with Trinitarian symbolism. The Lodge still stands. It is one of the most architecturally peculiar buildings in England.

Three miles north of Kettering sits Boughton House, sometimes described as the English Versailles, the country seat of the Dukes of Buccleuch since the seventeenth century. Along with the Watsons of Rockingham Castle, the Buccleuchs were joint lords of the manor of Kettering for centuries. The house is still in the family. The crocketed spire of the parish church of SS Peter and Paul, fifty-five metres high, dominates the town's skyline; its first known priest took up office in 1219 and the current building is largely fifteenth-century Perpendicular Gothic. The current Boughton House is open to the public on occasion. From the same north Northamptonshire ground that produced the rebels of Newton, the airmen of Grafton Underwood, and the world snooker champion of 2024 also came one of the more astonishing private picture collections in the British Isles, kept quietly in a country house that few visitors to Kettering ever see.