Mușatescu was born in Câmpulung-Muscel[1] to a family of middle-class intellectuals — his father was a lawyer while his mother was a writer.

He completed studies at the University of Bucharest, where he earned a degree in Law and one in Literature.

[1] Much of his work centers on provincial life in his native city, and includes political satires such as Titanic Vals (arguably, his most influential writing).

The 1964 movie Titanic Waltz, directed by Paul Călinescu and starring Grigore Vasiliu-Birlic, was adapted from his play.

He died in Bucharest and was buried in the city's Bellu Cemetery, next to his wife, actress Kitty Stroescu (1907–1990) and their son, Bogdan Mușatescu (1941–2016), also an actor.