In 1992, David wrote his first play, Burning Blue, which opened at The King'’s Head on London’'s fringe in 1995. His second play, Alice Virginia, premiered in London in 2003 with Andrew Halliday and Amanda Boxer as the secondary leads and Susannah York playing the title role.
In 2003., Greer directed the pilot episode of his six-part mockumentary, Ticket to Glory, a dark comedy about fame and misfortune. He wrote a screen adaptation of Ibsen'’s Ghosts for United Media.
In addition to his writing, he has been designing and renovating both commercial and residential spaces for the past 20 years. In 2005, Andrew Halliday joined the business full-time with the formation of HallidayGreer, a one-stop design operation with high-end projects in New York, California, Miami and London.