Chief Justice Roy Moore said his Christian faith meant he had to direct local officials not to issue marriage licenses to same-sex couples.
Graham, the son of evangelist Billy Graham, said that Moore "is a man who will stand up for what is right".
He said on a Facebook post: "Join me in praying for Judge Moore, and share your encouragement with him in the comments below."
The Supreme Court of the United States passed a law in June 2015 that meant every state would have to legalise gay marriage. It has faced resistance in more conservative states.
Moore had told local officials in Alabama to ignore the Supreme Court and refuse to allow gay couples to marry.
He was suspended without pay for the rest of his term. It means he has effectively been sacked as he will be too old to seek re-election at the term end, in January 2019.
Officials said he had violated judicial ethics with his guidance, which suggested local authorities could not issue marriage licences to gay couples.
He plans to appeal.
Moore, 69, has been suspended before. In 2003 he rejected a federal order to take down a Ten Commandments monument he had installed in a state court.
