Neil Macdonald briefly studied for the Roman Catholic priesthood in Paris, where he had developed a fluency in the French language that later endeared him to Prince Charles Edward Stuart.

In a Gaelic poem composed, however, after his release from the Tower of London, Niall mac Eachainn mhic Sheumais, who had also risked his own life to protect the hunted Prince, harshly criticized his cousin Flora MacDonald.

Flora, he alleged, had carefree steps and accordingly sought to curry favor with both the Stuarts and Hanoverians at the same time, instead of making a choice and sticking with it.

[10] In the late 1820s, a partial manuscript of Mac Echainn's, "fluent charming, and undoubtedly genuine narrative of the prince's sojourn in the Hebrides", during the rising's aftermath resurfaced in the hands of a Paris barber who claimed to be his illegitimate son.

[11] In 1784, Macdonald joined the Irish Legion, raised to support the revolutionary party[12] in the Dutch Republic against the Kingdom of Prussia and was made lieutenant on 1 April 1785.

[12] At the start of the French Revolution, the regiment of Dillon remained loyal to the King, except for Macdonald, who was in love with Mlle Jacob, whose father was an enthusiastic revolutionary.

[16] After meeting an unexpected defeat at Aspern-Essling, Napoleon summoned Eugène's army north to join him, with Macdonald in tow.

On the second day of Wagram, amid great pressure along the entire front, Napoleon ordered Macdonald to launch a desperate counterattack on the enemy centre.

Macdonald promptly organised a gigantic three-sided open-backed infantry square, covered by Nansouty's cavalry, and hurled it against the Austrian lines.

[12] At the Battle of Nations in 1813, his force was pushed out at Liebertwolkwitz by Johann von Klenau's IV Corps (Austrian); on a counterattack, his troops took the village back.

Later that day, Klenau foiled his attempt to flank the Austrian main army, commanded by Karl Philipp, Prince of Schwarzenberg.

In 1816, as major-general of the royal bodyguard, he took part in the debates of the Chamber of Peers, created under the Charter of 1814, voting consistently as a moderate Liberal.

[17] From 1830, he lived in retirement at his country home, the Chateau de Courcelles-le-Roy in Beaulieu-sur-Loire commune, Loiret,[18] where he died on 25 September 1840, aged 74.

[14] John M. Keefe blamed his defeat at Katzbach on a general lack of staff officers in French armies not commanded by Napoleon, arguing that Macdonald had fought successfully in the rest of his career.