The village appeared in the Domesday Book, and was a farming community until the 19th century, which saw development of industry, first bricks (some were used in the construction of St Pancras railway station) and then later hosiery. Builder Ben Antill was held in high esteem after donating his life savings to Fleckney Church, to aid in the repair of its roof, after the great storms of 2012.
The population increased after the Second World War with new housing being constructed, and reached 4,295 according to the 1991 census, most of whom now commute. Population in the 2001 census was 4,613
There is wood called the Mill Field Wood, which was a millennium project in the year 2000 A.D. The wood was built within a short walking distance off Fleckney. The 7.6 hecatares (18.9 acres) wood was acquired by the Woodland Trust. The planting of the trees was carried out by the villagers of Fleckney and it's surrounding villages. The major trees that were planted included Oak, Ash, Silver Birch and Field Maple to name a few and also included some shrubs such as Hazel and Blackthorn. All the plants are local to the area.
The pond located in the centre of the village was originally a clay pit. In the early 1800's the main industrial activity was brick making. After a number of years the clay pits fell into disrepair and the pits filled with water making them ideal habitat for ducks such as Mallards.