In memory of his daughter who was killed by an underage drunken driver, Leo McCarthy started Mariah's Challenge. The nonprofit <a href="index.php?page=&url=http%3A%2F%2Fwww.cnn.com%2F2012%2F06%2F14%2Fus%2Fcnnheroes-mccarthy-alcohol-challenge%2Findex.html">gives college scholarships to teenagers</a> who pledge not to drink while they're underage.
Portrait of a Hero: Leo McCarthy —
In memory of his daughter who was killed by an underage drunken driver, Leo McCarthy started Mariah's Challenge. The nonprofit gives college scholarships to teenagers who pledge not to drink while they're underage.
John Nowak/CNN
McCarthy adjusts holiday decorations at the memorial where his daughter Mariah was killed in Butte, Montana. Mariah and two of her friends were walking down a sidewalk in 2007 when a 20-year-old drunken driver hit them. Mariah, 14, was killed. Her two friends survived.
Portrait of a Hero: Leo McCarthy —
McCarthy adjusts holiday decorations at the memorial where his daughter Mariah was killed in Butte, Montana. Mariah and two of her friends were walking down a sidewalk in 2007 when a 20-year-old drunken driver hit them. Mariah, 14, was killed. Her two friends survived.
John Nowak/CNN
At Mariah's funeral service, McCarthy promised the teenagers in attendance that he would reward them if they stayed away from drugs and alcohol. Since then, his nonprofit has awarded nearly $150,000 in scholarship money.
Portrait of a Hero: Leo McCarthy —
At Mariah's funeral service, McCarthy promised the teenagers in attendance that he would reward them if they stayed away from drugs and alcohol. Since then, his nonprofit has awarded nearly $150,000 in scholarship money.
John Nowak/CNN
The McCarthys have several scrapbooks dedicated to their daughter. The images include family vacations, summer camp trips and many of Mariah's school drawings.
Portrait of a Hero: Leo McCarthy —
The McCarthys have several scrapbooks dedicated to their daughter. The images include family vacations, summer camp trips and many of Mariah's school drawings.
John Nowak/CNN
The family has left Mariah's bedroom untouched. "I took some pictures and immediately felt like I was intruding on a private moment," photographer John Nowak said. "I think Leo noticed, and he reassured me that her story needed to get out, and by taking these pictures we were making that happen."
Portrait of a Hero: Leo McCarthy —
The family has left Mariah's bedroom untouched. "I took some pictures and immediately felt like I was intruding on a private moment," photographer John Nowak said. "I think Leo noticed, and he reassured me that her story needed to get out, and by taking these pictures we were making that happen."
John Nowak/CNN
A portrait of Mariah sits on a table as McCarthy prepares to talk to a group of junior high and high school students in Boulder, Montana.
Portrait of a Hero: Leo McCarthy —
A portrait of Mariah sits on a table as McCarthy prepares to talk to a group of junior high and high school students in Boulder, Montana.
John Nowak/CNN
Mariah's Challenge is simple. Teens can go online and sign a pledge to not drink until they are 21 and not get into a car with someone who has been drinking. Toward the end of their senior year, if they have not been convicted of underage possession of alcohol, they are eligible to submit a scholarship application.
Portrait of a Hero: Leo McCarthy —
Mariah's Challenge is simple. Teens can go online and sign a pledge to not drink until they are 21 and not get into a car with someone who has been drinking. Toward the end of their senior year, if they have not been convicted of underage possession of alcohol, they are eligible to submit a scholarship application.
John Nowak/CNN
More than 140 teenagers have received $1,000 scholarships. "Mariah's Challenge stands for integrity, character and honesty and living a life of simple self-respect," McCarthy said.
Portrait of a Hero: Leo McCarthy —
More than 140 teenagers have received $1,000 scholarships. "Mariah's Challenge stands for integrity, character and honesty and living a life of simple self-respect," McCarthy said.
John Nowak/CNN
McCarthy hugs students and gives them advice. Many embrace him and tell him personal stories about how they've dealt with alcoholism in their family or among their friends. "It's really them, not me, that are seen in CNN Heroes," McCarthy said. "To them, it's growing up by changing this situation a generation at a time."
Portrait of a Hero: Leo McCarthy —
McCarthy hugs students and gives them advice. Many embrace him and tell him personal stories about how they've dealt with alcoholism in their family or among their friends. "It's really them, not me, that are seen in CNN Heroes," McCarthy said. "To them, it's growing up by changing this situation a generation at a time."
John Nowak/CNN
Nationwide, Montana routinely ranks in the top five per capita for drunken-driving fatalities. Those troublesome statistics, along with Mariah's story and other high-profile deaths, have led legislators to seek more aggressive ways to address the issue.
Portrait of a Hero: Leo McCarthy —
Nationwide, Montana routinely ranks in the top five per capita for drunken-driving fatalities. Those troublesome statistics, along with Mariah's story and other high-profile deaths, have led legislators to seek more aggressive ways to address the issue.
John Nowak/CNN
McCarthy prefers to be left alone as he prepares for each presentation. He gets emotional and recalls the exact details of his daughter's death, Nowak said.
Portrait of a Hero: Leo McCarthy —
McCarthy prefers to be left alone as he prepares for each presentation. He gets emotional and recalls the exact details of his daughter's death, Nowak said.
John Nowak/CNN
"When you first meet Leo, you realize how affable and intelligent he is," Nowak said. "He knows how teenagers initially react when presented with the idea of pledging not to drink for four years, but he also shares the pain of losing his daughter with everyone he meets."
Portrait of a Hero: Leo McCarthy —
"When you first meet Leo, you realize how affable and intelligent he is," Nowak said. "He knows how teenagers initially react when presented with the idea of pledging not to drink for four years, but he also shares the pain of losing his daughter with everyone he meets."
John Nowak/CNN
When a student completes Mariah's Challenge, they are awarded a scholarship and a medal as a sign of their commitment and perseverance.
Portrait of a Hero: Leo McCarthy —
When a student completes Mariah's Challenge, they are awarded a scholarship and a medal as a sign of their commitment and perseverance.
John Nowak/CNN
McCarthy's daughter Jenna nominated him for CNN Heroes. "Mariah is forever 14," he said. "I can't get her back, but I can help other parents keep their kids safe."
Portrait of a Hero: Leo McCarthy —
McCarthy's daughter Jenna nominated him for CNN Heroes. "Mariah is forever 14," he said. "I can't get her back, but I can help other parents keep their kids safe."
John Nowak/CNN