The criminal known as Lionmane was likely born in the 1930's, based on a predicted age to have started a criminal career in the 1950's, during the latter years of the career of the Catwoman.  While his true name is unknown, his large and proud physique and his leonine mane of hair made him a natural young recruit to the gang of the Catwoman.  Who gave him the name "Lionmane" is not known.

At one point just prior to her retirement, the Catwoman staged a massive jewelry heist and decided to bury her ill-gotten gains in Fagan's Wood outside of Gotham.  The brash young Lionmane challenged the Catwoman, insisting they would not bury the jewels but instead take them themselves.  He challenged the Catwoman to physical combat and while he administers a serious beating, she eventually gases him and leaves him unconscious and trussed up for the police.  Her recovery was long and became a story that she shared often with her daughter Helena.

In the 1980's, Lionmane was serving time on Gull's Island, a maximum security prison on an island in Gotham Harbor.  He coordinated a prison revolt, started by a large explosion then capturing the warden and making hostages of the guards.  He began to make a series of demands, unaware that the explosion that started his takeover had attracted the Huntress.

After the Huntress snatched the Warden from his grasp, she left Lionmane with a note that if he could beat her in personal combat, she would reveal the secret of Fagan's Wood.  Enraged at the reminder, Lionmane accepted the challenge and  the two fought it out on a rock in the middle of a throng of angry prisoners.  Summoning the spirit of her mother, Helena ultimately bested Lionmane, dispersing the prisoners  and allowing the police to round them up and rescue the hostages.  Unfortunately the only prisoner to escape was The Joker (Wonder Woman #278-280)

Any further activities of Lionmane are not recorded.