Nicolae MiÈu was born to a father of the same name, who was the Minister for Foreign Affairs in Romania. The younger Nicolae MiÈu also became a Romanian diplomat. MiÈu played at Wimbledon 10 times between 1919-30, making the third round in singles in 1922 and 1924, and the semi-finals of the 1920 All-England Plate, the consolation tournament for first and second round losers. He made the quarter-finals at Roland Garros in 1926, also playing there in 1925, 1927, 1929-31, and 1933. He played the World Hard Court Championships from 1920-23, making the semi-finals in singles in 1923, and he was a finalist in doubles in 1920 and 1922. MiÈu also made the semis of the World Covered Court Championship in 1919 and 1923.
MiÈu was a top player on the French Riviera, especially in 1919-20 when he won four tournaments. He won at Monte Carlo and Cannes in 1919, and won the Riviera Championship in 1919-20. He was runner-up at the 1930 Balkan Championships and in 1922 at Deauville.