He was born in Gotha, the fourth but eldest surviving son of Ernst I, Duke of Saxe-Coburg-Altenburg and Elisabeth Sophie of Saxe-Altenburg.

At first, they agreed to a common household of all seven brothers in the Schloss Friedenstein, though this arrangement endured only until 1676.

This was finally accomplished on 24 February 1680; Frederick kept Gotha, Tenneberg, Wachsenburg, Ichtershausen, Georgenthal, Schwarzwald, Reinhardsbrunn, Volkenrode, Oberkranichfeld, Orlamünde, Altenburg and Tonna.

In order to prevent future disputes between his descendants, he established primogeniture for his house in 1685 (with Imperial assent granted in 1688).

He ruined the finances of his small duchy, however, using them to maintain a standing army, which by the time of his death counted over 10,000 men.