Carpenter was born in Salisbury, the daughter of Captain Alexander Geddes, who was of an Edinburgh family, and Harriet Easton.

[1] She exhibited a portrait of Lord Folkestone at the Royal Academy in 1814, and a picture entitled 'The Fortune Teller' at the British Institution.

[2] Of Carpenter's Head of a Polish Jew, exhibited at the British Institution in 1823, a reviewer wrote: "It very rarely happens that a specimen of art like this is produced from the hand of a lady: Here are colour, light, strength and effect, and anatomical drawing".

[8] Their children included two noted painters, another William and Percy Carpenter, who both travelled and painted in the Indian subcontinent.

They eventually married, making Margaret the aunt to Wilkie Collins, novelist and friend to Charles Dickens.

She died in London on 13 November 1872, in her 80th year,[citation needed] and was buried with her husband on the western side of Highgate Cemetery.