Cardinal Beaton was the sixth and youngest son of eleven children of John Beaton (Bethune) of Balfour in the county of Fife, and his wife Mary, daughter of Sir David Boswell of Balmuto.
The Bethunes of Balfour were part of Clan Bethune, the Scottish branch of the noble French House of Bethune.
The Cardinal is said to have been born in 1494.
He was educated at the universities of St Andrews and Glasgow, and in his sixteenth year was sent to Paris, where he studied civil and canon law.
In 1519 King James V of Scotland named him ambassador in France.

In 1520, his uncle, James Beaton, Archbishop of Glasgow, named David Beaton Rector and Prebendary at Cambuslang.
After his uncle became Archbishop of St. Andrews in 1522, he resigned the position of Commendator of Arbroath in favour of his nephew.
In 1525 David Beaton returned from France and took a seat as Lord Abbot of Arbroath in the Scottish Parliament.
In 1528 the King named him Lord Privy Seal.

Between 1533 and 1542 he acted several times as King James V of Scotland's ambassador to France.
He took a leading part in the negotiations connected with the King's marriages, first with Madeleine of France, and afterwards with Mary of Guise.
In 1537 he was made coadjutor to his uncle at St. Andrews, with right of succession.

In December 1537 Beaton was made Bishop of Mirepoix in Languedoc on the recommendation of King Francis I, and consecrated the following summer.
Presumably he was ordained around that time.
Also in 1538 he was appointed a Cardinal by Pope Paul III, under the title of St Stephen in the Caelian Hill.
In February 1539 Cardinal Beaton succeeded his uncle as Archbishop of St. Andrews.
In 1544, he was made Papal legate in Scotland.

Politically, Beaton was preoccupied with the maintenance of the Franco-Scottish alliance, and opposing Anglophile political attitudes, which were associated with the clamour for Protestant reform in Scotland.

Relations became strained between James V and his uncle, Henry VIII of England, who sought to detach Scotland from its allegiance to the Holy See and bring it into subjection to himself.
Henry sent two successive embassies to Scotland to urge James to follow his example in renouncing the authority of the Pope in his dominions.
King James declined to be drawn into Henry's plans and refused to leave his kingdom for a meeting with Henry.
Hostilities broke out between the two kingdoms in 1542.
The Cardinal was blamed by many for the war with England that led to the defeat at Solway Moss in November 1542.
Cardinal Beaton was the sixth and youngest son of eleven children of John Beaton (Bethune) of Balfour in the county of Fife, and his wife Mary, daughter of Sir David Boswell of Balmuto. The Bethunes of Balfour were part of Clan Bethune, the Scottish branch of the noble French House of Bethune. The Cardinal is said to have been born in 1494. He was educated at the universities of St Andrews and Glasgow, and in his sixteenth year was sent to Paris, where he studied civil and canon law. In 1519 King James V of Scotland named him ambassador in France.
In 1520, his uncle, James Beaton, Archbishop of Glasgow, named David Beaton Rector and Prebendary at Cambuslang. After his uncle became Archbishop of St. Andrews in 1522, he resigned the position of Commendator of Arbroath in favour of his nephew. In 1525 David Beaton returned from France and took a seat as Lord Abbot of Arbroath in the Scottish Parliament. In 1528 the King named him Lord Privy Seal.
Between 1533 and 1542 he acted several times as King James V of Scotland's ambassador to France. He took a leading part in the negotiations connected with the King's marriages, first with Madeleine of France, and afterwards with Mary of Guise. In 1537 he was made coadjutor to his uncle at St. Andrews, with right of succession.
In December 1537 Beaton was made Bishop of Mirepoix in Languedoc on the recommendation of King Francis I, and consecrated the following summer. Presumably he was ordained around that time. Also in 1538 he was appointed a Cardinal by Pope Paul III, under the title of St Stephen in the Caelian Hill. In February 1539 Cardinal Beaton succeeded his uncle as Archbishop of St. Andrews. In 1544, he was made Papal legate in Scotland.
Politically, Beaton was preoccupied with the maintenance of the Franco-Scottish alliance, and opposing Anglophile political attitudes, which were associated with the clamour for Protestant reform in Scotland.
Relations became strained between James V and his uncle, Henry VIII of England, who sought to detach Scotland from its allegiance to the Holy See and bring it into subjection to himself. Henry sent two successive embassies to Scotland to urge James to follow his example in renouncing the authority of the Pope in his dominions. King James declined to be drawn into Henry's plans and refused to leave his kingdom for a meeting with Henry. Hostilities broke out between the two kingdoms in 1542. The Cardinal was blamed by many for the war with England that led to the defeat at Solway Moss in November 1542.
David Beaton