Somers was born in Freshwater, Isle of Wight, the eldest son of Herbert Haldane Somers-Cocks and the former Blanche Clogstoun. His godfather was Alfred, Lord Tennyson. Somers' father died when he was seven years old. He succeeded a distant relative as Baron Somers at the age of twelve. He attended Charterhouse School before going on to New College, Oxford. He was an able cricketer, and played 17 first-class games. In 1904, whilst a schoolboy at Charterhouse, he made 115 against Westminster, and two years later he made his first-class debut for Marylebone Cricket Club against Worcestershire, scoring 0 and 13. He rarely had enough time to play cricket, but in the 1920s he made a further 16 first-class appearances for Worcestershire, his highest score being 52 against Essex in May 1925. In later life he became both a vice-president of Worcestershire County Cricket Club and, in 1936, President of the MCC.
Somers was appointed Governor of Victoria in 1926, in succession to Lord Stradbroke. Aged 39, he was one of the youngest holders of the office. He "had charm and natural gaiety which won him popularity... warm and generous, he had a genuine interest in people, as well as a high sense of duty and leadership... a shrewd and successful governor". A Freemason, he was initiated into Household Brigade Lodge No.2614 under the United Grand Lodge of England some 18 years before he arrived in Victoria, and served as the Grand Master of the United Grand Lodge of Victoria between 1927 and 1932. Following the expiry of Lord Stonehaven's term as Governor-General in October 1930, Somers – as the longest serving state governor – was called upon to act as Administrator of the Commonwealth until Sir Isaac Isaacs took office in January 1931.
In 1929, at his own expense, Somers brought together teenage boys from different backgrounds in Australia to what was named Lord Somers Camp which continues to this day. The idea of the camp was based upon the Duke of York camps in the England that operated until the start of the Second World War. Back in England, he was appointed Chief Commissioner of the Boy Scouts in 1932, was deputy Chief Scout from 1935 to 1941, and was designated by Lord Baden-Powell, the founder of the Scout Movement, who had been Chief Scout of the World, as his successor as Chief Scout. He was appointed as Chief Scout of the British Empire in March 1941, on the death of Baden-Powell. He served until his death in 1944. He was succeeded by Lord Rowallan.
Family
Somers married Daisy Finola Meeking in 1921 and had issue, an only daughter:
Hon. Elizabeth Violet Virginia Somers Cocks, who married Major Benjamin Alexander Frederick Hervey-Bathurst, 2nd son of Sir Frederick Edward William Hervey-Bathurst, 5th Baronet.