[3] Leigh has a reputation at Westminster for his independence of mind as a "serial rebeller",[4] who is prepared to vote against his own political party if it conflicts with his own principles.

[12] His maternal grandfather, Colonel Cyril Denzil Branch MC, was a nephew of Prince Nikolai Golitsyn, the last Prime Minister of Imperial Russia.

[17] Leigh first stood for Parliament at the October 1974 general election, when he unsuccessfully contested Middlesbrough, coming second with 24.4% of the vote behind the incumbent Labour Party MP Arthur Bottomley.

[31] Early in 2008, as Chairman of the PAC, Leigh was embarrassed by relying on flawed Department for Transport (DfT) statistics to attack motorcyclists for tax evasion.

He was a member of the Treasury Financial Reporting & Advisory Board and, in 2010, Leigh became a delegate to the Parliamentary Assembly of the Council of Europe, speaking regularly and serving on the Culture, Science, Education and Media Committee.

[35] Leigh also supported Boris Johnson's call to George Osborne in 2011 for lowering the rate of taxation in the UK so as to assist its economic recovery following the credit crunch.

In 2012, Leigh, together with a record number of fellow Conservative MPs, including numerous Privy Counsellors, successfully voted against the Coalition Government's attempted railroading of House of Lords reform by limiting time for meaningful parliamentary debate on this major constitutional issue.

[40] In September 2014, Leigh criticised the Government's decision to allow mitochondrial replacement therapy to prevent the birth of the children with incurable diseases such as muscular dystrophy.

[41] In 2015, the French President François Hollande appointed him to the Légion d'honneur for his role as "a bridge between our parliaments, our governments and our societies", as stated by Ambassador Sylvie Bermann at his investiture.

[43][44] In March 2016, he joined three other Conservative MPs in "talking out" a Bill introduced by Green Party MP Dr Caroline Lucas, which aimed to reverse moves to privatise the NHS.

[50] On 1 March 2022, Leigh praised Home Secretary Priti Patel's 'proportionate response' over admission of refugees into the UK from the Russian invasion of Ukraine.

[61][62] He voted against recent amendments to the Health and Social Care Bill which has made permanent the permission for at-home medical abortions to take place.

[63] Following an interim report on the connections between colonialism and properties now in the care of the National Trust, including links with historic slavery, Leigh was among the signatories of a letter to The Telegraph in November 2020 from the "Common Sense Group" of Conservative Parliamentarians.

In June 2018 he suggested reforming the National Health Service, stating: "I personally feel we have to look at social insurance, which they have in France and Germany, because there is no room for increases in general taxation.

Christine Jardine, Cabinet spokesperson for the Liberal Democrats, condemned the image, stating: "Conservative MPs should not be cosying up to a far-right leader who has enforced homophobic and anti-democratic policies.

"[67] In November 2024, Leigh co-wrote a piece in The Guardian with Labour MP Diane Abbott opposing Terminally Ill Adults (End of Life) on Assisted Suicide Bill.

[69] In October 2017, the House of Commons overwhelmingly passed an Opposition motion to delay the introduction of Universal Credit and iron out problems with the system first.

[74] Leigh received the accolade of the Realm for "public and political service":[75][76] Leigh married Mary Goodman in London on 25 September 1984, the granddaughter of Countess Maria von Carlow and great-granddaughter of Duke Georg Alexander of Mecklenburg-Strelitz through her mother,[79] and the great-grandchild of the Arts patron Lady Ottoline Morrell and British politician Philip Morrell, through her father.

Sir Edward and Lady Leigh have six children (Natalia, Tamara, Benedict, Marina, Nicholas, and Theodore) and divide their time between homes in Westminster and his Lincolnshire constituency.