The younger son of William Henry Upjohn KC, he served in the Welsh Guards during the Second World War, reaching the rank of brigadier.

On 26 November 1963 he became a Lord of Appeal in Ordinary and was made additionally a life peer by the style title Baron Upjohn, of Little Tey in the County of Essex.

The Judicial Committee of the House of Lords would ideally sit with an odd number of judges, to ensure a clear decision.

Lord Upjohn's death raised the problem of an equally divided Appellate Committee.

It has been pointed out that, 'had Lord Upjohn been in favour of allowing the appeal, the application of the principle would have produced a disgruntled appellant whose victory had been snatched from under his nose: it may well be that such manifest injustice would have led to the case being reargued before a reconstituted court.