Rosman is an active supporter of fundraising for the Cystic Fibrosis Foundation and wishes to educate the public about the need for organ donation. Mackenzie's stepsister, Katelyn Salmont, lived with cystic fibrosis and underwent a successful double lung transplant in late 2005, her father Randy donating one organ. Both girls were featured in Teen People's "20 Teens Who Will Change the World". 7th Heaven produced a special episode about cystic fibrosis titled "Back in the Saddle" which featured Salmont as herself, and Rosman and Salmont rode horses together, as they did at home. In 2005, Salmont reappeared, post-transplant, on 7th Heaven (the episode entitled "X-Mas"), to describe the new life she'd been given. Salmont died of pneumonia and cystic fibrosis on Christmas 2008. Rosman also supports Childhelp Inc. and is an ambassador for the organization, which helps severely abused children. Rosman is also the national honorary chairman for CureFinders, a school fundraising program to help fund the search for a cure for cystic fibrosis.