One of the founding agents of what would eventually become SEMME, Anthony McHenry was dragged into a strange world when his father, who worked at Area 51, stole a Martian spacecraft. His father was attacked by the Head Alien, but Anthony and Linda Walkerton fought them off. Joining the government to pay off his father's debt, he became partners with Linda, battling menaces worldwide. Anthony eventually married, and had a son, Anthony Jr.; he even rose to command SEMME, establishing much of its organization. (Whether he was the first Big Boss is uncertain.)
However, tragedy would strike McHenry's life- his wife died under hideous circumstances, and his son was shot by Sal during the Year Zero event. McHenry eventually accompanied several SEMME squads on a mission into the Bermuda Triangle, where a Martian city lay underwater. He hoped to have a chance to use a Martian resurrection chamber on his son; unfortunately, he was badly wounded by Walky when he, in anger, dropped two storage capsules containing the remains of Sal's adoptive parents on the Head Alien. Before his wounds could be tended, McHenry was crushed by Monkey Master.