Buchanan was born in Brockville, Province of Canada, the third and youngest son of Alexander Buchanan and his wife Catherine (née McLean),[1] Scottish immigrants, but his parents returned to the United Kingdom shortly after he was born and he was brought up in Larne, where his father worked as a quarry manager.

[2] Buchanan joined William Sloan & Co, a Glasgow shipping firm, as an office boy when he was fourteen or fifteen, and was later promoted to be a clerk.

He realised that there was an untapped market in England for bottled Scotch whisky and set about producing his own, the Buchanan Blend, which is still available today.

[2] He owned properties in Kenya and Argentina and part-owned, with Lord Aberdeen, a 20,000-acre fruit farm in British Columbia, Canada.

He bought the logbook of HMS Victory and presented it to the British Museum, financed the fitting out of HMS Implacable as a training ship, and donated £125,000 to fund a wing at Middlesex Hospital in 1928 in honour of his late wife, £50,000 to restore the nave of St George's Chapel, Windsor, £10,000 to the University of Edinburgh to fund animal breeding research (later receiving an honorary Doctorate of Laws), £10,000 to fund a ward at the London Hospital, £5,000 to the West of Scotland Agricultural College, £2,500 to the Licensed Victuallers' School, and £2,500 to the Licensed Victuallers' Benevolent Institution.

[2] In 1928 Woolavington purchased the Will Longstaff painting Menin Gate at Midnight for 20,000 Guineas (equivalent to £21,000) and presented it to the Australian Government.

Buchanan was created a baronet, of Lavington in the County of Sussex, in the 1920 New Year Honours,[5] for "public and local services"[6] and was raised to the peerage in the 1922 New Year Honours as Baron Woolavington, of Lavington, in the County of Sussex,[7] for being a "generous supporter of many public and charitable objects".

[8] However, it is said that he paid £50,000 for his peerage, signing the cheque "Woolavington" and dating it 2 January – the day after the title was to be gazetted – so that the payment would bounce if he did not receive the honour he had been promised.

[10] On 5 December 1891, Buchanan married a young widow thirteen years his junior, Annie Eliza Bardolph (née Pounder).