He served as an officer in the Dutch States Army, and was successively commander of Rheinberg and governor of Bergen op Zoom.

George Frederick was born at Dillenburg Castle on 23 February 1606[1][2] as the second son of Count John VII 'the Middle' of Nassau-Siegen and his second wife, Duchess Margaret of Schleswig-Holstein-Sonderburg.

[7] George Frederick entered the service of the Republic of the United Netherlands and became captain of the infantry in 1627, and in 1633 also ritmeester of the cavalry.

[1][7][8] In 1638 George Frederick and his second cousin Prince Manuel Antony of Portugal[note 1] were captured by the Spanish near Geldern,[7][8] in 1639 the States-General paid a ransom of £ 1,000 for him.

John 'the Younger' had the imperial decree read out, and when his brothers demurred, he said as he stood up: "Der Kaiser wird uns scheiden!"

He had taken the precaution of obtaining a further imperial decree on 20 November 1623 against Countess Dowager Margaret and her sons, in which the Emperor strictly forbade impeding John's assumption of government, his taking possession of the land and his inauguration.

However, for a short period (1632–1635) this situation underwent a temporary change: during the Thirty Years' War, his brothers, who were fighting on the Protestant side, rebelled against John 'the Younger'.

[16] Count Louis Henry of Nassau-Dillenburg entered the service of King Gustavus II Adolphus of Sweden on 1 December 1631, who had landed in Germany on 24 June 1630 to intervene in favour of the Protestants in the Thirty Years' War.

[20] Countess Dowager Margaret, through the mediation of Louis Henry, turned to Gustavus Adolphus and asked for help against the machinations of her stepson John 'the Younger'.

On 14 February 1632 the Swedish king sent an order from Frankfurt to Louis Henry to provide military support for his first cousin John Maurice.

However, the latter soon restored the old order: in 1636, he again became the sole owner of his father's property, with the exception of Hilchenbach, which he left to William, and he again governed the city of Siegen alone.

[23] On 22 January 1645, after his return from Brazil, the latter, with his brothers George Frederick and Henry and an 80-man entourage, had forcibly occupied Siegen Castle and on 15 February had received the renewed homage from the citizens, albeit this time only for two thirds of the county.

[25] In 1645 John Maurice relinquished his rights to the Freudenberg district, granted by the will of 1621, in favour of his brother George Frederick.

[1][6] As governor of Bergen op Zoom, George Frederick was succeeded by his distant relative, Count Walrad of Nassau-Usingen.