Charles Beresford was the second son of the 4th Marquis of Waterford. He joined the Royal Navy in 1859, and started his training as a cadet at the naval training academy HMS Britannia. He became a lieutenant in 1874. He was a well-known and popular figure who courted publicity. He was widely known to the British public as "Charlie B" and considered by many to be a kind of personification of John Bull and indeed was normally accompanied by his trademark, a bulldog.
He entered Parliament as a Conservative in 1875, representing Waterford and retained his seat until 1880. Whilst an MP he continued to serve in the navy, becoming a commander in 1875. He was aide-de-camp to the Prince of Wales, later Edward VII, from 1875 until 1876, accompanying him on a visit to India. From 1878 until 1881 he was second in command of the royal yacht HMS Osborne. He was captain of the gunboat HMS Condor in 1882 when it took part in the bombardment of Alexandria during the Egyptian war of 1882 and won admiration amongst the British public for taking his ship inshore to bombard the Egyptian batteries at close range.
In 1885 he was elected as an MP again, this time for Marylebone, and re-elected in the general election of 1886. He constantly pushed for greater expenditure on the navy, resigning his seat in protest on this issue in 1888. The Naval Expenditure Act of 1889, which increased naval spending, was passed partly as a result of public pressure resulting from this action. From 1889 until 1893 he was the captain of HMS Undaunted, which was part of the Mediterranean fleet.
In 1897 he was promoted to rear-admiral and again entered Parliament, this time representing York. He retained this seat until 1900, although he spent much of his time in China represeting the Associated Chambers of Commerce, and from 1900 onwards was second in command of the Mediterranean fleet.
He returned to Parliament in 1902, this time for Woolwich, but resigned in 1906 when he was promoted to an admiral and appointed chief of the Channel Fleet. He was in command of the Mediterranean fleet from 1905 until 1907.
He had a public and bitter dispute with the First Sea Lord, Jackie Fisher, over the reforms which the latter was pushing through. He returned to Parliament, representing Portsmouth when his term with the Channel Fleet finished in 1909, staying until 1916 although he retired from the navy in 1911.