Isaac Pocock was born in Bristol on 2nd March 1782, the eldest son of Nicholas Pocock, the marine painter, by Ann, daughter of John Evans of Bristol. William lnnes Pocock was his brother. Isaac inherited his father's artistic talents and, about 1798, became a pupil of Romney. After Romney's death, he studied under Sir William Beechey. He acquired something of the distinctive style of each of his masters. William Hayley's son, Thomas Alphonso Hayley, was a fellow student under Romney and, in February 1799, Pocock accompanied Romney on a month's visit to the elder Hayley at Eartham. During this visit, Romney made drawings of his two pupils and Hayley addressed a sonnet to Pocock, beginning "Ingenious son of an ingenious sire".

Between 1800 and 1805, Pocock exhibited subject pictures and portraits at the Royal Academy and occasionally sent portraits during the next fifteen years. In 1807, his 'Murder of St. Thomas A'Becket' was awarded the prize of £100 given by the British Institution. In 1812, Pocock became a member of the Liverpool Academy and sent, to their exhibitions, painting's in both oils and watercolours. His last historical painting was an altar-piece for the new chapel at Maidenhead.

In 1818, Pocock inherited, from his uncle, Sir Isaac Pocock, some property at Maidenhead, and thenceforth, he mainly devoted himself to the dramatic arts. Pocock's first piece was a musical farce entitled 'Yes or No’. It was produced at the Haymarket on 31st August 1808, and acted ten times. Genest calls it a poor piece, but Oulton says it had some effective broad humour. It was followed by numerous similar productions. By far the most successful was 'Hit or Miss,' first given at the Lyceum on 26th February 1810, which was put on "at least thirty-three times". Pocock later aimed at a higher species of composition and converted some of the Waverley novels into operatic dramas. On 12th March 1818, his 'Rob Roy Macgregor, or Auld Lang Syne,' an operatic drama was first played at Covent Garden and others followed.

For some time, he lived in London and served in the Royal Westminster Volunteers, in which he was raised to the rank of major "by the suffrage of its members". He afterwards became a JP and DL for Berkshire, and was an active magistrate. Pocock died at Ray Lodge, Maidenhead, on 23rd August 1835 and was buried in the family vault beneath Cookham Church. He had married, on 24th August 1812, Louisa, daughter of Henry Hime of Liverpool, and left three daughters and a son, Isaac Innes Pocock (1819-1886), a barrister and poet.