Huffman was arrested in March as part of authorities' Operation Varsity Blues investigation, and subsequently pleaded guilty to paying $15,000 (£12,370) to try and rig a college entrance exam to help her eldest child Sofia win a place at an elite university.
As part of a plea deal, officials recommended a prison term of between four to 10 months - and Huffman will discover her fate in September.
Speaking about the controversy surrounding her close friend, Longoria told Entertainment Tonight she's proud to see how the 56-year-old has conducted herself during the headline-grabbing scandal.
"I think she has a heart that is bigger than the sun and that's the Felicity I know and that's the woman I choose to support and love," she said. "She was humbled by what happened and I think she did handle it with as much grace as she could in that situation."
Longoria's words come after Huffman's "Otherhood" co-stars Angela Bassett and Patricia Arquette also voiced their support for Huffman, with the latter saying: "I haven't spoken to her, but I feel that she's sincerely truly sorry and feels she made a humongous mistake. I think she dealt with it the best way that you can deal with it, but I know she's probably carrying a lot of shame and guilt and all that stuff."
"I think she's handling it like a grown-up person. She's handling it like a grown woman," Bassett added. "It's a brave thing and a courageous thing."