Olivier's father chose the camp of Charles de Blois and the King of France in the Breton War of Succession and was the military commander defending the city of Vannes when the English besieged it in 1342.

Hereafter, he was raised in the court of King Edward III alongside John IV de Montfort, a future claimant of the Ducal throne of Brittany.

Olivier's mother Jeanne, eventually married her fourth husband, an English military commander of King Edward III.

After ten years in England, Olivier, then twenty-three, accompanied King Edward III and John IV de Montfort at the head of a Breton-English force to Brittany in 1359 as part of a guerrilla campaign near Poitou.

Under the reign of the new King, John II "The Good" of France, Olivier was reconciled to the French Crown in 1360 as part of the Treaty of Brétigny, drafted on 8 May.

The marriage produced two daughters: In 1363 Olivier was still on the side of the Breton-English Montfortists and one of the commanders of the Montfort troops who failed to take Nantes, but managed to hold Bécherel.

Monfortistes were entrenched there and John IV attempted to overcome the numerical inferiority of his army by attacking the Breton-French camp by surprise.

Isolated from the bulk of his army, Charles de Blois was surrounded and killed in the melee, while Bertrand du Guesclin, the French Commander, was captured but released later with a ransom in 1365.

Olivier evidently raged "I would rather give myself to the devil than have an English neighbor" A fortnight later, the Gâvre castle was surprisingly burnt down.

In 1366 Olivier was sent to Paris as the Breton ambassador to ensure that Charles V, King of France, complied to the guarantees of the status of an independent Brittany.

A few months later, Olivier formalised his change of allegiance, by signing a charter establishing the suzerainty of the King of France over Josselin, even though it was located in the heart of Brittany.

In the same year, during a raid by the English General Robert Knolles outside Paris, Olivier advised the King in a cautious tactic, a defensive strategy to avoid a pitched battle as the French were not sufficiently prepared; Knowles was eventually turned away from capital.

The Constable and Olivier shared the military command, the former leading the fight in Auvergne and Rouergue, while the second attacked the English positions of Poitou, Saintonge and Anjou during the summer.

In revenge, Olivier executed fifteen prisoners and developed a reputation for not hesitating to mutilate captive enemies, cutting off arms or legs.

Duke John IV chose to sign a new treaty of alliance with England explaining to France that he was forced to host English troops in order to counter Olivier's militant presence in Brittany.

In 1373 in response to this, King Charles V ordered the Constable on 1 March to seize the Duchy and ensure the support of Olivier, by giving him the lordship of Guillac.

Du Guesclin and Olivier started a propaganda war to discredit the Breton nobility of Duke John IV.

Abandoned by most of the Breton nobility, Duke John IV was forced into exile and crossed the English Channel on 28 April 1373.

Marguerite was the widow of Jean de Beaumanoir, a hero of the Breton nobility, who faced the English at the battle of Trent, she had three daughters.

With these unions, Olivier V is linked to the largest noble families of Brittany.In 1380 after the death of du Guesclin, King Charles VI, crowned at the age of twelve, gave Olivier the rank of Constable of France on 28 November, with the support of the Duke of Anjou, but despite the opposition of the Dukes of Berry and Burgundy, all three uncles of the King.

Olivier led the French Royal army on 27 November to victory in the Battle of Roosebeke during which twenty-five thousand men were massacred.

The Constable was able to gain a tactical advantage against the inexperienced bourgeois militias, artisans, and merchants who were crushed by the seasoned French troops, who then engaged in massive looting.

A decision to reinstate a tax which had been abolished by the previous King, started a revolt from the citizens of Paris, the Maillotins uprising, in March 1382.

King Charles VI's absence from Paris while supporting his troops in Flanders gave hope to the revolters that royal power had weakened.

It appears that Olivier was positioning his family as under the terms of the Treaty of Guérande, if Duke John IV had no male child, Jean de Blois, son of Joan, Duchess of Brittany, would then be the Ducal heir apparent.

Olivier eventually agreed to pay a large sum and to give to Duke John IV the forts of Blain, Josselin and Jugon Le Guildo.

Since the King was only twelve years old, Olivier played a special role, as the historian Françoise Autrand qualified, as an "uncle".

In 1392 on Olivier's return to Paris, an attempt was made to assassinate him by Pierre de Craon, allegedly at the instigation of Duke John IV.

Louis of Orleans offered to his brother King Charles VI that the government of Brittany be therefore entrusted to Olivier, to prevent it passing under English domination, however Philip the Bold became regent of the Duchy.

After mentioning in his will a wish to return the sword of the Constable, Olivier de Clisson died in Josselin on 23 April 1407 at the age of 71.