Black was born 2 May 1968 in West London. He is the son of advertising executive Brinsley Black (1930-2011), named as one of the best-dressed Englishmen in the inaugural issue of Men in Vogue in 1965, and his second wife, Lady Moorea Hastings (1928-2011). She was the daughter of the Labour Peer and academic Francis Hastings, 16th Earl of Huntingdon (1901–1990), and Cristina Casati Stampa di Soncino (1901–1953), the only child of Camillo, Marquis Casati Stampa di Soncino (1877-1946) and Italian heiress and eccentric patroness of the arts Luisa Casati (1881–1957). Through his mother's earlier marriage to politician and diarist Woodrow Wyatt, Black has one older half-brother, Pericles (born 1963).
In 2007, Black proposed to Joanne Cash, an Oxford-educated barrister, and they married in December of that year.
The couple live in Kensington and Chelsea. They have a baby daughter.
Upon graduating from university, he joined Booz Allen Hamilton as a business analyst, where he worked predominantly in the Financial Services practice.
Black was brought into AGB Research by Mark Booth to help turn around the market research business, owned by Robert Maxwell. After the disappearance of Maxwell the business went into administration.
Black joined Smythe, Dorward Lambert as their sixth employee. Black became the Sales and Marketing Director of the leading employee communication consultancy of its time with 100 employees and a turnover of £10 million. The consultancy was sold to Omnicom in 1996.
Black is also on the Advisory Board of Teaching Leaders.
Black, along with co-founder Sebastian Bailey, started The Mind Gym at his kitchen table in 2000. The privately owned company designs and sells corporate learning and development programmes. It is most well-known for its 90-minute long training sessions known collectively as “Workouts". The company serves 53% of S&P100 and 61% of FTSE100 companies via 400 qualified Mind Gym Coaches delivering in 40 countries. It operates from four offices (New York, London, Dubai, Singapore).
Under The Mind Gym, Black co-authored three books (The Mind Gym: Wake Your Mind Up, The Mind Gym: Give Me Time, The Mind Gym: Relationships). The first in the series, The Mind Gym: Wake Your Mind Up reached number two on amazon.co.uk and was translated into 27 languages. It won “Management Handbook of the Year” at the MCA Management Writing Awards in 2005.
In 2012, Black renamed the company from “The Mind Gym” to “Mind Gym”.
Mind Gym has been recognised for Innovator of the Year 2012 (Real Business), Great Place To Work 2012 (Great Place To Work Institute), Learning Company of the Year 2013 & 2014 (Learning & Performance Institute), HR Consultancy of the Year 2014 (Personnel Today), Training Industry Watch List 2014 (TrainingIndustry.com).
He writes a regular column in the business section of The Sunday Telegraph on the human aspects of business.
Black's Parent Gym, is a 6 week parenting programme for parents of children aged 2–11. It is funded by Black’s commercial enterprise, Mind Gym and applies its corporate training knowledge to help people in arguably the hardest job in the world - being a parent.
It was piloted in 2010 and now runs 150 programmes every year for parents in areas of multiple deprivation in London and Brighton and Black hopes to roll it out nationwide. London Major, Boris Johnson described it as “Just about the most hopeful thing I have seen.” 
A study carried out by Canterbury Christchurch University found that all parents interviewed two months or more after completing the programme reported that their relationships with their children had improved. The evaluation also found that three quarters of these parents considered that relationships within the family as a whole had improved.
Parent Gym has been awarded the CANparent Quality Mark which certifies that the scheme is evidence based, monitored and evaluated to improve parent-child relationships.
In 2014 Parent Gym was recognised with a “Highly Commended” at the Responsible Business Awards in Building Stronger Communities
- Eden, Richard (7 February 2009). "David Cameron finds new 'guru'". Daily Telegraph (London).
- [unreliable source?]
- [dead link]
- "Acquisition: The motives behind Omnicom’s latest buy - Omnicom has had its chequebook out again, this time to buy up Fleishman-Hillard. The move mirrors the approach it has taken to building its advertising agency networks | PR & public relations news | PRWeek". Mediaweek.co.uk. 1997-04-18. Retrieved 2013-10-06.
- http://www.teachingleaders.org.uk/supporters,39.html[dead link]
- Ivy Pasic (2009-08-01). "Meet the savvy company revolutionising the way we use - and improve - our grey matter". EasyJet Magazine.
- Personnel Today (2001-05-01). "Quick fix".
- Companies House (2014). "Annual Report and Financial Statements Year Ended 31 March 2014. Company Number 03833448".
- John-Paul Flintoff (2005-01-15). "John-Paul Flintoff meets the authors of the best-selling book 'The Mind Gym', a persuasive cross between corporate training and self-help". FT.com.
- Management Today (2005-11-01). "‘Winning Words MT presents the winners of the second annual MCA Management Writing Awards’".
- Companies House (2014). "Company Number 03833448".
- Real Business (2005-11-01). "Growing Business Awards 2012: The winners".
- Great Place To Work (2012). "Best Workplaces in the UK - Small Category".
- Learning & Performance Institute. "Learning Company of the Year 2013 & 2014".
- Jo Faragher (2014-12-09). "Personnel Today Awards 2014 winners: Mind Gym named Consultancy of the Year". Personnel Today.
- Training Industry (2014). "Watch list".
- Hannah Richardson (2010-10-08). "Business coaches offer skills to struggling parents". BBC News.
- Ravi Mattu (2010-10-06). "Give more power to your people". Financial Times.
- Octavius Black (2010-08-09). "I don’t have time to think". Financial Times.
- Robert Booth (2012-05-18). "Mind Gym tycoon wants to roll out free parenting lessons across country". The Guardian.
- Boris Johnson (2010-10-11). "The road to a university place must begin when a child is five". The Telegraph.
- Stephanie Hagan (2014-07-03). "Reflections on the 2014 Building Stronger Communities Award". Business in the Community.