During the First Anglo-Dutch War of 1652–1654, De Ruyter agreed to join the expanding Dutch fleet as a junior flag-officer or commandeur, a rank broadly comparable to that of commodore, commanding a Zeelandic squadron of "director's ships", which were privately financed warships, after he had initially refused the post on the grounds that others were better qualified for it.
De Ruyter proved his worth under the supreme commander lieutenant-admiral Maarten Tromp.
The rank of admiral-general was reserved for the stadtholder, but at the time, no-one held that appointment.
The main function of De Ruyter's squadron was to convoy outbound or returning Dutch merchant ships through the English Channel, where they were vulnerable to attacks from English ships based at Portsmouth or Plymouth.

In August 1652, a convoy of around 60 Dutch merchant ships left the Netherlands for the Mediterranean, initially with an escort of 10 warships.
The convoy was joined off the coast of the Spanish Netherlands by a further escort commanded by De Ruyter of between 20 and 30 fighting ships.
The exact number of Dutch fighting ships involved in the subsequent battle is unclear, but De Ruyter sailed with 21 warships from all five of the Dutch admiralties, two large Dutch East India warships and six fireships.
Additional warships may have joined him on route to the convoy and at least one warship was damaged before te subsequent battle and returned to port.
On 15 August 1652, the convoy and its escort were sighted by an English fleet commanded by General at Sea George Ayscue with around 45 ships.
Three of these were warships more powerful than any in the Dutch fleet, but like in De Ruyter's fleet many of the others were small armed merchant ships rather than purpose-built warships.
On the afternoon of 16 August 1652, Ayscue attempted to attack and capture the Dutch merchant ships with around nine of his strongest and fastest warships, but De Ruyter counter-attacked, leaving the convoy unprotected, and he surrounded those English warships that had attacked.
The ensuing mêlée battle continued until nightfall, as the outnumbered English ships could rely on their stronger gun batteries to keep the Dutch at bay.
Most of the hired English merchant ships neither attempted to aid their warships nor pursue the Dutch merchant ships.
As Ayscue was defeated in his aim of capturing or destroying Dutch merchant ships, and as De Ruyter fought off an attack by a potentially superior force by a bold attack on its strongest ships, De Ruyter clearly won this battle of Plymouth and saved the convoy.
He also fought at the battle of Kentish Knock and the battle of the Gabbard during this war.

Tromp's death during the battle of Scheveningen ended the war, and De Ruyter declined an emphatic offer from Johan de Witt to assume supreme command because he considered himself 'unfit' and also feared that it would bring him into conflict with Witte de With and Johan Evertsen, both of whom had more seniority.
Later, De Ruyter and De Witt became friends.
Colonel Jacob van Wassenaer Obdam then became the new Dutch supreme commander of the confederate fleet.
De Ruyter at first refused to become Obdam's naval 'counsellor and assistant', but later was persuaded by De Witt to accept and remained in the service of the Dutch navy in that post until he accepted an offer from the Admiralty of Amsterdam to become their vice-admiral on 2 March 1654.
He relocated with his family to that city in 1655.
During the First Anglo-Dutch War of 1652–1654, De Ruyter agreed to join the expanding Dutch fleet as a junior flag-officer or commandeur, a rank broadly comparable to that of commodore, commanding a Zeelandic squadron of "director's ships", which were privately financed warships, after he had initially refused the post on the grounds that others were better qualified for it. De Ruyter proved his worth under the supreme commander lieutenant-admiral Maarten Tromp. The rank of admiral-general was reserved for the stadtholder, but at the time, no-one held that appointment. The main function of De Ruyter's squadron was to convoy outbound or returning Dutch merchant ships through the English Channel, where they were vulnerable to attacks from English ships based at Portsmouth or Plymouth.
In August 1652, a convoy of around 60 Dutch merchant ships left the Netherlands for the Mediterranean, initially with an escort of 10 warships. The convoy was joined off the coast of the Spanish Netherlands by a further escort commanded by De Ruyter of between 20 and 30 fighting ships. The exact number of Dutch fighting ships involved in the subsequent battle is unclear, but De Ruyter sailed with 21 warships from all five of the Dutch admiralties, two large Dutch East India warships and six fireships. Additional warships may have joined him on route to the convoy and at least one warship was damaged before te subsequent battle and returned to port. On 15 August 1652, the convoy and its escort were sighted by an English fleet commanded by General at Sea George Ayscue with around 45 ships. Three of these were warships more powerful than any in the Dutch fleet, but like in De Ruyter's fleet many of the others were small armed merchant ships rather than purpose-built warships. On the afternoon of 16 August 1652, Ayscue attempted to attack and capture the Dutch merchant ships with around nine of his strongest and fastest warships, but De Ruyter counter-attacked, leaving the convoy unprotected, and he surrounded those English warships that had attacked. The ensuing mêlée battle continued until nightfall, as the outnumbered English ships could rely on their stronger gun batteries to keep the Dutch at bay. Most of the hired English merchant ships neither attempted to aid their warships nor pursue the Dutch merchant ships. As Ayscue was defeated in his aim of capturing or destroying Dutch merchant ships, and as De Ruyter fought off an attack by a potentially superior force by a bold attack on its strongest ships, De Ruyter clearly won this battle of Plymouth and saved the convoy. He also fought at the battle of Kentish Knock and the battle of the Gabbard during this war.
Tromp's death during the battle of Scheveningen ended the war, and De Ruyter declined an emphatic offer from Johan de Witt to assume supreme command because he considered himself 'unfit' and also feared that it would bring him into conflict with Witte de With and Johan Evertsen, both of whom had more seniority. Later, De Ruyter and De Witt became friends. Colonel Jacob van Wassenaer Obdam then became the new Dutch supreme commander of the confederate fleet. De Ruyter at first refused to become Obdam's naval 'counsellor and assistant', but later was persuaded by De Witt to accept and remained in the service of the Dutch navy in that post until he accepted an offer from the Admiralty of Amsterdam to become their vice-admiral on 2 March 1654. He relocated with his family to that city in 1655.
Michiel de Ruyter