Kirk is best known as the lovable teen heartthrob Mike Seaver, of the award winning series Growing Pains. He entertained audiences worldwide as the charming troublemaker. He is also known to every Christian as "Buck Williams" from Left Behind: The Movie -- based on the NY Times runaway best selling novels by Tim LaHaye and Jerry Jenkins.

But much more noteworthy than his acting career was his conversion to Christianity. Kirk was not raised in a church-going home and describes himself as a devout atheist from a very young age. By the age of 8 he was so convinced there was no God that he laughed at those who thought there was. But that all changed one afternoon as he sat in his sports car pondering the first Gospel message he had ever heard.
Since becoming a Christian, Kirk has been a dedicated follower of Christ, making the most of every opportunity to further the Gospel. He speaks in churches, and at community events across the country. He is also the producer and host of The Way of the Master television program.

Kirk and his wife, Chelsea, have six children and live in southern California.