Following graduation, he moved to New York City, where he served as an actor in any theaters. In 2004 Long became cast as a lead on the critically acclaimed but short-lived The WB drama series Jack & Bobby, and afterward appeared in many TV pilots and satrred in movies, such as Ghost Rider and Sydney White.
He performed the lead role in the short-lived ABC drama series The Deep End in 2010. Long also had the recurring role of Joey Baird in the AMC drama series Mad Men, and in 2012 became cast in the ABC pilot Gilded Lilys, formed and produced by Shonda Rhimes. Shonda afterward cast Long in her medical drama Private Practice in a recurring role as Dr. James Peterson. In 2013, became cast as a lead in another ABC drama series, Lucky 7.
