From 1983 to 1984, Heywood worked as an economist at the Health and Safety Executive, before moving to the Treasury, and became the Principal Private Secretary to the Chancellor of the Exchequer then Norman Lamont at the age of 30, having to help mitigate the fallout from Black Wednesday after less than a month in the job. He remained in this role throughout the 1990s under ChancellorsKenneth Clarke and Gordon Brown. He was economic and domestic policy secretary to Tony Blair from 1997 to 1998, before being promoted to be the Principal Private Secretary to Prime Minister Tony Blair in 1999. He stayed in this position until 2003, when he left the civil service in the wake of the Hutton Inquiry where it emerged that he said he had never minuted meetings in the Prime Ministerial offices about David Kelly, a job he was required to do. He became a managing director of the UK Investment Banking Division at Morgan Stanley where he was embroiled in the aftermath of the collapse of Southern Cross Healthcare. Upon Gordon Brown becoming Prime Minister in 2007, Heywood returned to government as Head of Domestic Policy and Strategy at the Cabinet Office. He later resumed the post of Principal Private Secretary, as well as being appointed the Downing StreetChief of Staff after the resignation of Stephen Carter. In 2010, after David Cameron became Prime Minister, Heywood was replaced as Chief of Staff by Edward Llewellyn and as Principal Private Secretary by James Bowler. He returned to the civil service and was subsequently appointed the first Downing Street Permanent Secretary, a role created for the purpose of liaising between the Cabinet Secretary and the Chief of Staff within the Cabinet Office.
Cabinet Secretary
On 11 October 2011 it was announced that Heywood would replace Sir Gus O'Donnell as the Cabinet Secretary, the highest-ranked official in Her Majesty's Civil Service, upon the latter's retirement in January 2012. It was also announced that Heywood would not concurrently hold the roles of Head of the Home Civil Service and Permanent Secretary for the Cabinet Office, as would usually be the case. These positions instead went to Sir Bob Kerslake and Ian Watmore respectively. On 1 January 2012, Heywood was knighted and officially made Cabinet Secretary. In July 2014 it was announced that Kerslake would step down and Heywood would take the title of Head of the Home Civil Service in the coming autumn. In September 2014, Heywood duly succeeded Kerslake., Heywood was paid a salary of between £195,000 and £199,999, making him one of the 328 most highly paid people in the British public sector at that time. In June 2013, he visited The Guardians offices to warn its then editor, Alan Rusbridger, that The Guardians involvement with Edward Snowden could make it a target for "our guys" in British intelligence and "Chinese agents on your staff". He was criticised when he vetoed release to the Chilcot Inquiry of 150 letters and records of phone calls between Tony Blair and President George W. Bush before the 2003 Iraq War.
Illness and death
After years of heavy smoking, Heywood was diagnosed with lung cancer in June 2017 and took a leave of absence from his position in June 2018 owing to his illness. He retired on health grounds on 24 October 2018. Over a week later, he died on 4 November 2018, aged 56.
Personal life
In 1997, Heywood married Suzanne Cook. Together they had three children, including twins. Suzanne is a former civil servant who moved into the private sector: she has been managing director of the Exor Group since 2016 and chair of CNH Industrial since 2018.