The story of Caerlaverock Castle is interwoven with the story of the Maxwell family, one of the leading families in Scotland, who built the castle and still own it. The family first appears on the record in the early twelfth century in Roxburghshire. In about 1220, the King of Scotland granted Maccus, son of Undwin, estates in areas known as Melrose, Eildon of Darnick and Maxwell Haugh. At this last location, close by the King's own castle of Roxburgh, Maccus chose to build his own castle. The first castle built was sited too near the salt marshes of the Solway. In the 1270s construction began about 200 meters to the north on the present castle and the original castle was abandoned.

The peace and prosperity of the Maxwells came to an abrupt end in 1296 with the invasion of Scotland by Edward I of England, "Hammer of the Scots". With their estates so close to the border, Caerlaverock became a focus of attention and they were inevitably caught up in the power struggle that followed. In the aftermath of the invasion, Edward I forced many Scots to swear loyalty. Among them were Herbert de Maxwell and his son, John. But the Scots soon began to resist their new English overlord. Edward was undaunted and in 1300 invaded Galloway, one of the strongest centers of resistance. Caerlaverock Castle was a prime target for his wrath. Although is was a marginal incident in the turbulent events at the time, the siege of Caerlaverock in 1300 became one of the best known military operations of the war because of the detailed account of it written by a member of the besieging army:

"Caerlaverock was so strong a castle that it feared no siege before the King came there, for it would never have had to surrender, provided that it was well supplied, when the need arose, with men, engines and provisions. In shape it was like a shield, for it had but three sides round it, with a tower at each corner, but one of them was a double one, so high, so long, and so wide, that the gate was underneath it, well made and strong, with a drawbridge and a sufficiency of other defenses. And it had good walls, and good ditches filled right up to the brim with water. And I think you will never see a more finely situated castle, for on one side can be seen the Irish Sea, towards the west, and to the north the fair moorland, surrounded by an arm of the sea, so that no creature born can approach it on two sides, without putting himself in danger of the sea. On the south side it is not easy, for there are many places difficult to get through because of the woods and marshes and ditches hollowed out by the sea where it meets the river."

Edward came with 87 knights and 3,000 men. They pitched their colorful camp; their tents adorned on the outside with heraldry, their interiors strewn with herbs and flowers. Then siege engines were sent for as it was observed "the castle will not be taken by check with a rook, but there will be projectiles thrown and engines raised and poised". The siege was not protracted and Lord Maxwell's garrison of 60 men soon surrendered. Some were hanged from the castle walls, the rest were allowed to walk free.

Caerlaverock Castle remained an English stronghold until 1312. Despite their pro-Balloil stance during the prolonged wars with England, the Maxwells retained their estate at Caerlaverock demonstrating the Borderer's ability to make the most from both sides. In 1312 Sir Eustas Maxwell, keeper of the castle at that time, was granted forgiveness of a debt of 22 pounds from the English King, no doubt considered a small price to pay for his loyalty. But he repaid the gesture by declaring almost immediately for Robert Bruce, King of Scots. He was besieged in the castle but held out. After the raising of the siege he was granted a charter of annual rent by Robert I "for demolishing the castle" in line with Robert Bruce's wider policy of removing all strongholds that could be used by an invading force.