Elaine Floyd was born and brought up in Hopkinstown, near Pontypridd, in Wales. She has lived for many years in Mountain Ash, near Aberdare. She graduated from Lady Margaret Hall Oxford University with a degree in English. She married Morien Morgan (d.1997) and she has three sons.

Elaine Morgan began writing in the 1950s after winning a competition in Statesman, successfully publishing, then joining the BBC when they began produce her plays for television.Morgan's works include popular dramas, newspaper columns, and a series of publications on biological anthropology.

Morgan has written for many television series since 1955. The 32 credits for her work on IMDB include:

• Campion two episodes (1989)
• The Life and Times of David Lloyd George (1981)
• Testament of Youth (adaption of the book) (1979)
• How Green Was My Valley (adaption of the book) (1975)
• Nine episodes of Dr. Finlay's Casebook (1963—1970)

She has won two BAFTAs and two Writers' Guild awards. She also wrote the script for the Horizon documentary about Joey Deacon, the disabled fund-raiser. This won the Prix Italia in 1975. She was honoured with the Writer of the Year Award from the Royal Television Society for her series of Testament of Youth.

In 2003 she started to write a weekly column for the Welsh national daily newspaper, The Western Mail.

She was awarded an honorary D.Litt. by Glamorgan University in December 2006, an honorary fellow of the University of Cardiff in 2007, and awarded the Letten F. Saugstad Prize for her "contribution to scientific knowledge".

Morgan was appointed Officer of the Order of the British Empire (OBE) in the 2009 Birthday Honours for services to literature and to education. She was elected a Fellow of the Royal Society of Literature the same year.

Morgan first became drawn into scientific writing when reading popularizers of the savannah hypothesis of human evolution such as Desmond Morris. She described her reaction as one of irritation because the explanations were largely male-centered. For instance, she thought that if humans lost their hair because they needed to sweat while chasing game on the savannah that did not explain why women should also lose their hair as, according to the savannah hypothesis, they would be looking after the children. On re-reading Desmond Morris's The Naked Ape she encountered a reference to a hypothesis that humans had for a time gone through a water phase, the so-called aquatic ape hypothesis. She contacted Morris on this and he directed her to Alister Hardy. Her first book The Descent of Woman (1972) was originally planned to pave the way for Hardy's more academic book, but Hardy never published his book. Morgan's first publication was mentioned by E. O. Wilson in 1975, comparing it to other 'advocacy approaches' such as The Imperial Animal as an 'inevitable feminist' counter, but describing the method as less scientific than other contemporary hypotheses. She accepted this criticism and so her later books were written on more scientific basis or more "po-faced" as she herself described it. As an outsider and a non-scientist she claims to have encountered hostility from academics. Consequently many of her books seem to be written as much to counter the many arguments put forth against the Aquatic Ape Theory as to advance its merits. Her position is summarised in her website. The story of Morgan's quest to have the aquatic ape hypothesis taken seriously was chronicled in the 1998 BBC documentary "The Aquatic Ape".

Morgan's version of the AAH has achieved much popular appeal, but has never achieved significant acceptance or serious scrutiny within the scholarly community. Despite this, Morgan continues to promote the theory, with invitations to speak at universities and symposia including a TED talk in 2009.

Her most recent book, Pinker's List, is a response to Steven Pinker's The Blank Slate, in which she rejects his claim to objectivity and argues that the "blank-slate" beliefs he caricatures have long been extinct.

Morgans earlier works as a playwright include:

• The Waiting Room: A Play for Women in One Act (Samuel French Ltd, 1958)
• Rest You Merry: A Christmas Play in Two Acts (Samuel French Ltd, 1959)
• Eli’r Teulu: Comedi Dair Act (Gwasg Aberystwyth, 1960)
• The Soldier and the Woman: A Play in One Act (Samuel French Ltd, 1961)
• Licence to Murder: A Play in Two Acts (Samuel French Ltd, 1963)
• A Chance to Shine: A Play in One Act (Samuel French Ltd, 1964)
• Love from Liz (Samuel French Ltd, 1967)

Morgan's later books on anthropology included:

• The Aquatic Ape, 1982, Stein & Day Pub, ISBN 0-285-62509-8
• The Scars of Evolution, 1990, Souvenir Press, ISBN 0-285-62996-4
• The Descent of the Child: Human Evolution from a New Perspective, 1995, Oxford University Press, ISBN 0-19-509895-1
• The Aquatic Ape Hypothesis, 1997, Souvenir Press, ISBN 0-285-63377-5
• The Naked Darwinist, 2008, Eildon Press, ISBN 0-9525620-30

Other works:

• Falling Apart: The Rise and Decline of Urban Civilisation, 1976, Souvenir Press Ltd. ISBN 0-285-62234-X
• Pinker's List, 2005, Eildon Press, ISBN 0-9525620-2-2