It is not certain whether or not this man was ever procurator. The text in
question reads, simply: "So Vitellius [the Legate of Syria, not to be
confused with the man who would later become emperor] sent Marcellus, a
friend of his, to take care of the affairs of Judaea." This implies but
does not necessarily mean that he was ever officially in charge of that
region. Louis H. Feldman, in his translation of the the Antiquities,
hypothesizes that Marcellus was put in charge temporarily.
It is also possible that this Marcellus is the same person as Eprius Marcellus, who was a respected consul in 60 or 61 and 74, during the reigns of Nero and Vespasian, and was governor of Asia from 70 to 73. It is also possible that this Marcellus is the same as Augustus Caesar's nephew M. Marcellus, but that seems less likely.
Ancient source: Antiquities 18.4.2. (Eprius Marcellus: Histories 2.53, 2.95, 4.6-10, 4.42).