The name Smørum is first recorded in Canute IV's gift letter to the Bishop of Lund from 1085. The first part of the name means "Butter" (Danish: Smør) while the suffix -rum means "place".
The village of Smørumnedre was originally smaller than the neighbouring village of Smørumovre but it was expanded with large areas of single family detached housing in the 1960s and 1970s. It was formerly the seat of Ledøje-Smørum Municipality which was merged with Ølstykke Municipality to form Egedal Municipality.
Oticon, a major manufacturer of hearing aids, has its headquarters in Smørumnedre. The building was inaugurated in 2005. Novo Nordisk opened Novo Nordisk Diabetes Center in Måløv in 1991 and now houses 2,300 employees. A new building, Diabetes Research House, broke ground in 2014 and will be completed in 2016 at an expected cost of DKK 750 millions.
The local football club is Ledøje-Smørum Fodbold which plays in Danmarksserien. They play their home games at Smørum Park and Ledøje Stadium. Ledøje-Smørum Fodbold is part of Ledøje-Smørum Idrætsforening. Smørum Golf Club is based to the south of Smørumnedre.
Smørumovre boasts a well-preserved village environment. The village originally consisted of two rows of farms situated to the north and south of a village green with a small pond. The village green was later built over with various buildings, including a forge, an inn workshops and residences for field workers and craftsmen. The old school, which overlooks the pond, is now home to Ledøje-Smørum Local Historic Archives. Located on the eastern outskirts of Smørumovre, Smørum Church dates from c. 1170. The murals in the chancel and nave date from c. 1500. The manor house Edelgave is situated in the southwestern corner of the village. It was built in 1782-91 by Andreas Kirkerup.