The name stems from the local Aboriginal name of "Kincumba" meaning "towards the rising sun" or "to tomorrow". A large open flat rock area at the highest plateau of Kincumba Mountain, which commands panoramic views of the region, was used by Kuringgai people as a meeting place and camp. Being the highest open position in the region, it was first to receive the morning sun as it broke over the eastern horizon Tasman Sea/Pacific Ocean, and so this area was also referred to as "towards tomorrow". Signs of habitation in the Kincumber area include axe-grinding grooves and rock engravings on Kincumba Mountain. Due to the freshwater creek, water access from Brisbane Water and the Hawkesbury River, and an abundance of old rainforest timber in the surrounding valley hills, Kincumber was one of the earliest settlements on the Central Coast, supplying wood for the needs of the growing colony at Sydney in the early 19th century.
Boat building became an early local secondary industry after timber-getting, to meet the primary necessity of water transport. Boat-building along Kincumber Creek in Kincumber continued until the early 21st century.
Kincumber Was once home to a Monazite processing plant that processed mineral sands that were mined in the local area, The plant was operated on the edge of Kincumber industrial estate, and backed on to Kincumber creek, the site "lot500" now abandoned still retains higher than average levels of radiation and has been deemed unsafe for development.
And dating back to the mid 1980s there was no local shopping center, and by the late 1980' the local shopping center was funded by a former world tennis player John Newcombe. 
At a federal level, Kincumber is within the Division of Robertson. Previously held on a safe margin by Jim Lloyd of the Liberal Party, the seat changed hands in the 2007 Federal Election, and was held by the Australian Labor Party's Belinda Neal. In 2010 the seat was won by Labour member Deborah O'Neill.