Emily Head, who plays Rebecca in the soap opera, and presenter Gaynor Barnes, a patron of the charity, cut the ribbon at the new Second Chance centre on Almshouse Lane near The Ridings.
The charity was established more than 30 years ago but it is hoped the new centre will provide better facilities to help people who have suffered brain injuries rebuild their lives.
Gaynor said: "It's a very special charity for me, I became a patron some 13 years ago after I lost my sister-in-law at the age of 44 to brain injury and it devastated our family.
"I felt afterwards I wanted to do something in her memory in my own quiet way. So to be involved with a brain charity such as Second Chance Headway has been fantastic.
"My sister-in-law passed away but so many people do recover and you can see that life can go on.
"I've seen how important Second Chance's work is to people who come here and their families. It's not just the practical support it's the emotional support as well."
Emily, whose character in Emmerdale suffered a brain injury, said: "Brain injury doesn't mean you can't live a life after and that is something that Second Chance especially is extraordinary at doing."
She became involved with the charity when she visited their facilities to research her character.