Headington was invested in GK Films with British Academy Award-winning producer Graham King from 2007 until 2012. He subsequently formed two production companies, Tango Entertainment and Ley Line Entertainment.
As a film producer/executive producer, Headington has worked on numerous projects including Hugo (co-producer) and World War Z (EP credit).
Headington produced Angelina Jolie's feature directorial debut, In the Land of Blood and Honey. The movie won the Stanley Kramer for “(an) achievement or contribution (that) illuminates provocative social issues in an accessible and elevating fashion.” He was an executive producer on Gore Verbinski's animated film Rango.
Other productions include The Young Victoria, The Tourist, Edge of Darkness, The Rum Diary, and the TV miniseries Camelot.
In 2013, Headington partnered with grammy award winning music producer Max Martin to produce the musical "&Juliet." The play premiered in London at the Shaftesbury theater in November 2019. It received nine Olivier Award nominations in 2020, winning three.