The three floored mansion, constructed of local Ham Hill stone, was built circa 1598 by Sir Edward Phelips, Master of the Rolls to Queen Elizabeth I. Some suggest architect William Arnold is responsible for the design, though it has yet to be substantiated. The house is distinguished by Dutch gables decorated with stone monkeys and other creatures. The many large, mullioned windows, an innovation of their day, give the appearance that the principal façade is built entirely of glass; a similar fenestration was employed at Hardwick Hall in Derbyshire. On the top floor, the windows of the gallery are interspaced by statues of the 'nine worthies' dressed in Roman costume. Inside, two broad stone staircases give access to each floor; during wet weather, the Phelips children would lead their ponies up these stairs to ride in the long gallery.
The house, like many Elizabethan mansions, is built in an 'E' shape. On the ground floor was the great hall, kitchens and pantries, on the upper floors, retiring rooms for the family and honoured guests. Over the centuries, the layout and use of rooms changed: Elegant drawing and dining rooms evolved on the ground floor, on the first floor, a magnificent panelled library and bed rooms, including Lord Curzon's secret bath concealed in a wardrobe.
As in all houses of the Elizabethan era, it had no corridors; the rooms led directly from one to another. This changed in the late 18th century when a façade from a nearby mansion at Clifton Maybank (which was being demolished) was used in a renovation of Montacute, thus providing the much needed corridor. Now, with the new frontage in place, the house was virtually turned around: The 'Clifton-Maybank' façade becoming the front entrance of the house, and the impressive former front elevation now overlooking a grass lawn surrounded by flower borders, rather than the original entrance courtyard. The small pavilions that flanked the demolished gatehouse still remain, resembling twin summer-houses with their ogee shaped roofs.
Perhaps the most notable feature of the house is the long third floor long gallery, spanning the entire top floor of the house. Originally used as an area for indoor exercise during inclement weather, today, it is used by the National Portrait Gallery to display part of their collection.
Living in the Montacute area since at least 1480, the Phelipses continued to reside in the mansion until the early 20th century, when the family fortune finally ran out. In 1915, the house was first let to George Nathaniel Curzon, 1st Marquess Curzon of Kedleston, then to the Enos family, Americans famous for their pharmaceutical products. Finally in 1929, the house was sold to philanthropist Ernest Cook who presented it to the Society for the Protection of Ancient Buildings, and from that Society, it passed to the National Trust. It was one of the Trust's first great houses.
The name "Montacute" is presumed to be derived from the Latin "Mons Acutus", referring to the small but still quite acute hill located to the west of the village. The house and village have often featured as locations for films. Several scenes of the 1995 film version of Jane Austen's novel Sense and Sensibility were filmed at Montacute.