He belonged to the Caecilii Metelli, one of the most prominent aristocratic families in the mid to late Roman Republic.
Marcus was the third of four sons of Quintus Caecilius Metellus Macedonicus.
The following year, Metellus became proconsular governor of Corsica and Sardinia, serving until 111 BC.
During his tenure, Metellus suppressed an insurrection on the island of Sardinia, for which he celebrated, upon his return to Rome, a triumph in Quintilis (July) 111 BC.
Marcus's younger brother, Gaius Caecilius Metellus Caprarius, also celebrated his own triumph on the same day, for his victories in Thrace.