[1] He is best known for developing the astrophysical simulation code Cloudy, for his work on physical processes in ionized plasmas, and investigations of the chemical evolution of the cosmos.

[2] From 1978 to 1980 he was at the Institute of Astronomy, Cambridge where he worked with Martin Rees on International Ultraviolet Explorer observations of radio galaxies.

[16] He is a co-author on the influential[17] 2006 textbook Astrophysics of Gaseous Nebulae and Active Galactic Nuclei, written with Donald E. Osterbrock of Lick Observatory and the University of California at Santa Cruz.

A noted science communicator, Ferland has given popular-level talks at the Smithsonian Institution, the Cleveland Museum of Natural History, and numerous clubs, organizations, and classes across the Bluegrass region.

In 2016 he received Catedratico de Excelencia Guillermo Haro from the National Institute of Astrophysics, Optics and Electronics, (Tonantzintla, Puebla, Mexico).