Can a male member of the Greek Orthodox Church of America join the Knights of Columbus? I hope so.
I’m sorry to have to disappoint you, but, so far as I know, the answer is no. Here are the requirements for the Knights of Columbus from the Knights’ web site:
Q: What are the requirements?
A: Membership requirements are that he be a practical Catholic gentleman, who is 18 years of age or older.
Q: What is a practical Catholic?
A: A practical Catholic is one who is in union with the Holy See and who practices the precepts of the Catholic Church (source).