Edward I, on his march south after the defeat of Wallace at the Battle of Falkirk in 1298, surveyed the site of the castle on the peninsula extending into the south end of the Castle Loch (lake).  His idea was to have a defensive castle near the border to assist in keeping English control of Scotland.  The first attack on the castle came a year later, in 1299, when Robert de Coningham, the Constable of Caerlaverock, attacked the garrison with a small force of Scots.  Robert was repelled and his head displayed on the tower.  In 1301 the Scots attacked with 5,000 men and were still repelled.  Finally, in 1306, Scots captured the castle only to lose it in 1307 to a force led by the Prince of Wales, using catapaults and ballistas. 

After Edward Bruce,  King Robert I's immediate younger brother, (and later Earl of Carrick and King of Ireland), captured the castle in 1311, the castle remained under Bruce control for the next 22 years.  During this time, Bruce met with the Earl of Carlisle and on January 3, 1323, they signed the treaty of Lochmaben, in order to bring peace to the border area that had been wasted in the battles between Scotland and England.  However, King Edward III of England still wanted war, so he had the Earl of Carlisle executed for treason.  In 1333 after the Battle of Halidon Hill, where Alexander Bruce, then Earl of Carrick was killed, Lochmaben Castle was surrendered to Edward III and remained in English hands for the next 50 years.

Eventually, Archibald Douglas laid seige to the castle in 1384, causing it to be surrendered on the 9th day.  During the next century, the Douglas family became so powerful that the King felt compelled to curb their influence.  In the course of a violent quarrel in 1452, King James II stabbed the Earl to death!!!  James finally defeated the Douglas family at the Battle of Battle of Arkinholm, May 1, 1455, and the castle then came under the Crown.

Between 1409 and 1424, the Carruthers family at Mouswald received numerous grants of land from the powerful Archibald, Earl of Douglas, for "service done and to be done".  Added to Mouswald were lands in Middlebie, Dornock, Hoddam, Westwood, Rockcliffe, Logan-tenement, Hetlandhill, and Tundergarth.  Andrew, 5th Laird of Mouswald, led the family for most of that period.  The importance of this family is seen, not only in the acquisition of land, but also in the appointment of Andrew's brother, Simon, as Commissioner of the West March, and another brother, Nigel, as Chaplain of the Abbot of Paisley, near Glasgow.  The fortunes of the Carruthers family at Mouswald seemed to ride on the fortunes of the Douglas family.

Andrew, 5th Laird Mouswald, was succeeded by his first son, John, 6th Laird Mouswald.  John became 1st Baron Carruthers, or Baron Mouswald, when King James II united all his land into one free barony on August 20, 1452.  At this time, Lochmaben Castle was still under control of Douglas.  He had appointed in 1446, at a salary of £40 per year, John Carruthers of Mouswald to be Captain of Lochmaben Castle, a position that he held until 1454.  After the Battle of Sark, fought in 1449, one of the greatest battles against the English ever fought in Dumfriesshire, the victorious Scots lodged their most important prisoners in Lochmaben Castle.  John Carruthers is also mentioned in the Exchequer Rolls as the receiver of large payments for household expenses in his role as Captain of the castle, on the occasion of visits of the King and Queen to Lochmaben.

However, the battles between James II and the Douglas family finally took their toll on the Carruthers family of Mouswald, recipients of land and power from the Douglas's.  In 1454, owing to the treachery of a gate porter who let the attackers in, Lochmaben Castle was taken by a group led by the Laird of Johnstone's two sons, Herbert Johnstone and Matthew Johnstone, of Pettinain.  John Carruthers and his sons were captured and imprisoned.  John Carruthers, 1st Baron Mouswald, not only lost captaincy of the Castle, but also lost his life as historians infer that he was either killed at the time of the castle's capture, or he was put to death, or died in prison.  On November 18, 1454, his oldest son, Archibald, received sasine as 2nd Baron Mouswald.  The Carruthers of Mouswald still remained a significant family in the region, though.  Archibald's younger brother, Sir Simon, was later named Warden of the West March.

James II kept the Johnstones in control of the castle.  Herbert Johnstone received the pay as Captain of the Castle after July, 1454.  James II was preparing for his final assault on Douglas and wanted Lochmaben Castle in the hands of a family loyal to him.  The Laird of Johnstone served James, and was rewarded for his service, at the Battle of Arkinholm, May 1, 1455.  The Earl of Douglas fled to England, but his brothers, the Earls of Moray and Ormond and Lord Balvany continued the fight, plundered Annandale and sent the spoils as a present to their mother, then in Carlisle.  The Laird of Johnstone attacked the convoy with 200 men.  Archibald Douglas, Earl of Moray, was killed and his head sent as a trophy to James II.  Johnstone received more land from James after going with him that same year to take Threave Castle, the great stronghold of the Douglases in Galloway.  Disputes in politics must not have carried over into personal lives as the Laird of Johnstone had a daughter who married Archibald Carruthers, 2nd Baron Mouswald.  The Johnstone family eventually amassed enough land to be named Marquess of Annandale and Earl of Hartfell.

The Lochmaben Castle seems to have not played a role in the 1484 Battle of Lochmaben where Carruthers of Holmains was significant in repelling the Douglas and English invasion of Scotland. 

In 1503, James IV spent his honeymoon with Margaret Tudor at Lochmaben Castle and added the great hall.  The Lord Treasurer of Scotland recorded that James spent 46s 8d to play cards with Lord Dacre, Warden of the English March.  A few years later, the same Lord Dacre had the gruesome task of identifying the mutilated body of the Scottish King after the Battle of Flodden.

James V is said to have spent the night before the Battle of Solway Moss, in 1542, at the castle.  He died two weeks later.

The story of Lochmaben Castle starting in the 16th century is a story of the feuds between the Johnstones and the Maxwells.  In 1545, the castle was surrendered to English King Henry VIII in exchange for the release of Lord Maxwell, but by the end of 1546, it was back in Scot hands.  After Queen Mary and her army had pursued Moray and the Protestant lords over the border in 1565, Darnley and the Queen spent the night at Lochmaben Castle, where they were entertained by the Master of Maxwell.  In 1568, Mary's supporters were in turn driven out of the castle by the Regent Moray.  Thereafter, the castle ceased to be a Royal Residence and became a barracks for the soldiers who tried to keep the peace on the Western March.  In 1585, Maxwell held the whole countryside except for Lochmaben Castle, which was under the command of the Johnstones.  Maxwell captured Johnstone in Dumfries and threatened to hang him unless the castle surrendered.  It did. 

The most famous siege of the castle was in 1588 when Lord Maxwell, a Catholic, landed at Kirkcudbright in an attempt to overthrow the Protestant Monarchy of Scotland and England.  Though Maxwell occupied the castles of Threave, Langholm, Lochmaben, and Caerlaverock, Scotland's King James VI reacted with such speed that only at Lochmaben did David Maxwell hold out.  James, with the aid of artillery borrowed from England's Queen Elizabeth, succeeded after a 5 day siege in forcing the Lochmaben garrison to surrender on a written promise, purporting to come from the King, guaranteeing the lives of the captain and his men.  However, this safe conduct was repudiated by the King and David Maxwell, along with five others, was hung in front of the gates of the castle.

In 1592, the castle was taken by the Earl of Bothwell, nephew of Queen Mary's Lord Bothwell.  Bothwell entered disguised as a woman and left open an entrance for his followers.  Scots soon had the castle back from Bothwell.

The castle must have been kept in reasonable repair until at least 1628, as that year fines were allocated for the repair of the castle.  However, after that, it was allowed to fall into ruin, with its masonry used as a quarry.  The Annandale House on High Street in Lochmaben is said to have been built of these blocks.  Today, almost 400 years later, the castle is in a high degree of ruin.  However, in the last few years, the access to the site has been created by Historic Scotland, including signage on the road from Lochmaben, access road to the castle, signage at the castle and parking at the castle.  Given the history of the castle in the conflicts affecting Scotland, this is an important historical site to visit, should you be in the area.