He previously taught screenwriting and production in the Film and Media Studies Program at Johns Hopkins University.

[1] His low-budget debut feature, Hamilton, made on 16 mm film with a cast of non-professional actors from Baltimore, proved a "minor miracle", wrote Richard Brody in The New Yorker.

[2] Porterfield's Putty Hill again revolves around a small working class community in Baltimore city, combining documentary and narrative traditions.

[3] His 2013 feature, I Used to Be Darker, was co-written by Amy Belk and starred musicians Ned Oldham and Kim Taylor alongside newcomers Hannah Gross and Deragh Campbell.

It premiered at The 2013 Sundance Film Festival[4] and was released commercially in the United States, France, Germany, Austria, and South Korea.