|The following is based on the spin off novel by Keith R. A. DeCandido and some details might contradict canon.|
Zachary Harkin was the ranking GDI officer on the Philadelphia at the time of the attack that ushered in the Third Tiberium War.
His wife, Doctor Elisa Scarangello was there as well. Harkin believed that Nod was no longer much of a threat, and Kane was dead, and thus he and Jack Granger did not get along well. One of his trademarks was his oak desk that he brought with him everywhere, which had been in his family for four generations.
He was alarmed that the Goddard Space Center had been overrun and they needed to evacuate the Philadelphia, but by then it was too late and only moments before a missile destroyed the station.
He and his wife were both killed when the Philadelphia was destroyed.