The law firm is an outgrowth from the firm of McCune and Greenlee, whose senior partner was the Honorable Baron C. McCune, a Federal District Judge for the Western District of Pennsylvania.
Greenlee, Richman, Derrico & Posa was formed in 1964 by Gaylord W. Greenlee, Stephen I. Richman, Patrick C. Derrico and Paul Posa.
The firm has gone through some name changes over the years, becoming Greenlee, Richman, Derrico, Posa & Harrington and later Greenlee, Derrico, Posa, Harrington & Rodgers.
Due to the death of Gordon Harrington, the firm became Greenlee, Derrico, Posa & Rodgers, until Mr. Rodgers left the firm.
It then became Greenlee, Derrico & Posa for the interim, until July 2017, when it became Greenlee Derrico Posa, LLC.