After high school, he joined the USAF, serving in the Vietnam War, eventually earning the rank of colonel.

Baxter confronted his ex-wife Patsy, and was forced by the Hellcat to release the Avengers from Brand captivity.

As security chief, he aided the Secret Empire and its leader, Professor Power, in an attempt to start World War III.

[12] Roxxon hired him and Angar the Screamer to lead a group of operatives in a twofold mission: infiltrate and destroy S.H.I.E.L.D.

[16] Mad-Dog gained superhuman powers as a result of bionic engineering and cellular augmentation by the Roxxon Mutagenic Department and by the third Secret Empire.

His teeth can emit a foaming chemical poison, to which he himself is immune, which can induce paralysis and possibly death if it enters a victim's bloodstream through Mad-Dog's bite.

He now possesses a large animalistic appearance, with pointed ears, claws on both his hands and feet, and a coat of fur on his limbs and torso.

[volume & issue needed] Robert Baxter has received combat training from the U.S. Air Force.