David McMahon joined Ken Burns and Florentine Films in 1999 as an assistant editor on Jazz.  Following stints at PBS’s public affairs series, Frontline, and at National Geographic Television and Film, McMahon returned to Florentine in 2003 as a co-producer of The War, a seven-part series that first appeared on PBS in 2007. McMahon also co-produced The National Parks: America’s Best Idea, which premiered on PBS in 2009 and won an Emmy Award for outstanding nonfiction series. 

With Burns and Lynn Novick, he wrote and produced The Tenth Inning, a two-part, four-hour follow-up to their nine-part series Baseball.

He is currently writing and producing a Florentine Films production about the five black and Latino teenagers convicted in the Central Park Jogger case in 1989.