He spent several years in Saudi Arabia as a young child where his father was in the oil business and then later moved to Houston.
In 1997 he was accepted to the Julliard School’s drama division and graduated with a BFA.
He was nominated twice for the Lucille Lortel Award for Outstanding Actor when he performed in some off-Broadway plays.
He first gained recognition for his role in the 2003 film Soldier's Girl. He played the central role of Calpernia Addams, a trans-gendered woman dating Army soldier Barry Winchell (played by Troy Garity). Winchell was subsequently murdered because of his sexuality and his relationship with Addams. Of the role, HDH said:
"Not even my excellent training at Juilliard prepared me for my first movie role, where I played a transsexual who falls in love with a military guy in Soldier's Girl. Here I was, this 6'3" 190-pound lanky kid from Chickasha, Oklahoma, not knowing how to begin being a woman. So I saw documentaries about transsexuals, I lost twenty-five pounds, and I put on prosthetic boobs and hips to become that character. There were times I'd look in the mirror and wonder 'what am I doing to my life here? My dad is going to kill me!' But the reason I went into acting was to be able to play parts as complicated and important as this one. In playing a transsexual, I got the chance to help change people's perspective about other people and that is a powerful thing. I'm playing a swashbuckling bandit in my next film, but I'll always be proud of Soldier's Girl."
He won a Gotham Award for Breakthrough Actor and was nominated for several other awards, including a Golden Globe, for his work in this film.
HDH played Aaron Tyler in the acclaimed, short lived 2004 TV series Wonderfalls, which was co-created by Bryan Fuller. Fuller has cast HDH in the lead role of Ned in his new series, Pushing Daisies.
This weeks Hump Day Hottie is ~ Lee Pace