Mark Valley was born in the state of New York in the city of Ogdensburg according to his biography. He graduated in United States Military Academy in the year 1987 and got the Bachelor of Science degree in the engineering and mathematics. He then worked in Berlin and he played Rugby in the US military team. He was in the Berlin Yanks Rugby Football Club and he served in military in Gulf War. His daughter was born in the year 1987 and she is called Sherrie. He got married in the year 2008 to a co-star in Fringe but they also got a divorce in just one year of the marriage.

Mark Valley got the first role to play in The Innocent in the year 1993 and he was still serving in the US Army based in Germany. He got the role where he had to play Father Pete in the Another World in the year 1993. Afterwards, he took up the role where he was Jack Deveraux at the NBC Daytime soap opera under the name of Days of Our Lives in 1994-1997. He played like a Detective Eddie Arlette, who is American police office in London and it was for the short lived show called Keen Eddie.

He was playing as Brad Chase for Boston Legal which is the spin-off for the television series of The Practice. He appeared in the Television series called ER where he was Richard Lockhart and he was playing as ex-husband to Abby Lockhart. In the year 2008, he was playing as a FBI agent called John Scott at Fringe. He was playing also in the Human Target in the lead role.

He had to join the Body of Proof regulars in the year 2012 and he was playing like Det Tommy Sullivan who is the love interest of Dana Delany. He was the co-star of Delany in the short lived series called Pasadena. He had played in many movies including Big Time, Jericho, The next Best Thing, The Siege, Some Girl, Breast men, The Innocent, Live, Shrek The Third, Zero Dark Thirty, Stolen, Live by Night, Batman: The Dark Knight Returns and Ferdinand. He has a net worth of 3 million dollars with the salary which is around 300,000 per year.