[11] Directed and co-written by MacMahon, the story was told through twelve ethnically and musically diverse musicians who auditioned for and participated in those pioneering recording sessions; The Carter Family, the Memphis Jug Band, Elder J.E.

Burch, The Williamson Brothers, Dick Justice, Charley Patton, The Hopi Indian Chanters, Joseph Kekuku, Lydia Mendoza, the Breaux Family, Mississippi John Hurt, and Blind Willie Johnson.

[12] The film was the result of ten years of intensive field research and postulated a radically new take on American history, namely that America was democratized through the invention of electrical sound recording and the subsequent auditions the record labels held across North America in the late 1920s, which were open to every ethnic minority and genre of music.

[3][4][5][7][6] During production of the American Epic documentary series, MacMahon directed and co-wrote The American Epic Sessions, a documentary film in which a sound engineer restored the fabled long-lost first electrical sound recording system from 1925 and twenty contemporary artists paid tribute to the momentous machine by attempting to record songs on it for the first time in 80 years.

[11][7][22] The film starred Steve Martin, Nas, Elton John, Willie Nelson, Merle Haggard, Alabama Shakes, Jack White, Taj Mahal, Ana Gabriel, The Avett Brothers, Rhiannon Giddens, and Beck.

[11] The American Epic Sessions employed a diverse line-up of performers both ethnically and musically to represent the breadth of cultures that were first given a national platform through the invention of this recording machine.

[34] MacMahon was nominated by the British Academy Film Awards as a Breakthrough Talent for directing The American Epic Sessions.