The Guardians were the bodies of good and evil, light and dark, calm and chaos. The White Guardian saw that the Universe was was on the verge of descending into chaos. The Black Guardian (his opposite) wanted this. He summoned the Doctor and sent him on a quest to find the six pieces of the Key to Time. Once put together, the Key would stop the Universe for a few seconds, enabling the White Guardian to restore balance. When the Doctor finally assembled the Key, the White Guardian was able to repair the damage. Before the Black Guardian could get the Key, the Doctor dispersed it again. The Doctor eventually become in one of the many games played by the Eternals-the race for the Enlightenment Crystal. The White Guardian warned the Doctor that there was ore to the Enlightenment Crystal than ever the Eternals realized. The White Guardian will always exist along side the Black Guardian.

The White Guardian was in The Ribos Operation, The Armageddon Factor and Enlightenment.