Mr. O'Brien has maintained a strong working relationship with Pacific Sun, U.S. Male, and Diamond Pictures. He is very gifted and has worked in videos which involve 10 categories. These include smooth, European scenes and also muscle men.

Marc has performed with a variety of other stars including Julien Salieri, David Bathory as well as Leonardo Santangelo. Of all of his costars, you can find Marc O'Brien appearing most frequently with Miguel Sabroso. The two of them have been in 2 films together. The list of films in which they have performed together consists only of two items: Legion Of Muscle and Fraternity Rush.

The list of movies in which Mr. Marc O'Brien appears contains Legion Of Muscle, Muscle And Cum Vol. 4 and Fraternity Rush. The two series in which Marc O'Brien has acted are Legion Of Muscle and Muscle And Cum.