Penn won the Oscar for best actor last month for his portrayal of slain gay rights activist Harvey Milk.
Last weekend, activist and radio personality Tom Gregory was the winning bidder and paid $12,500 for a costume Penn wore in the film version of Milk's life.
The proceeds from the sale will go to benefit equally Variety -- The Children's Charity of Southern California and the Hetrick-Martin Institute, home of the Harvey Milk High School, in New York.
The Clothes off Our Back Foundation presided over the online auction of Academy Award-nominated costume designer Danny Glicker's specially created ensemble as seen in "Milk."
Focus Chief Executive Officer James Schamus made the announcement about the auction Wednesday.
"We congratulate Tom Gregory on owning a piece of film history, and applaud his generous contribution," Schamus said in a statement. "The benefits to Variety and the Harvey Milk School are tangible in terms of the dollar amounts. What's even more gratifying is how the participation of all concerned validates Harvey's legacy of people getting involved, getting inspired, and making a difference for the next generation."
"The story of Harvey Milk only highlights the shame of those who vote to deny marriage equality to lesbians and gay men," Gregory added.