Courtney Heironimus is a fictional character from the Japanese science fiction franchise Mobile Suit Gundam SEED.
Courtney is a ZAFT test pilot with prodigal sense of piloting, that is known to have tested a large amount of ZAFT mobile suits. Before joining ZAFT he was a civilian with technology background.
He first tested the mass production version of the ZGMF-1017 GINN, followed by the ZGMF-515 CGUE and other ZAFT units. He is also known to have been the test pilot of the first ZAFT-built Gundam, the YMF-X000A Dreadnought. However, he did not possess the spatial awareness needed to control the DRAGOON system it was designed to test, and the unit was later test piloted (and subsequently stolen) by clone Prayer Reverie, who was able to test these systems.
Near the end of the Bloody Valentine War, he was the test pilot for the prototype ZGMF-X999A ZAKU Trial Type. During this testing, he encountered a large squadron of Earth Alliance GAT-02L2 Dagger L mobile suits during test runs of the ZAKU in the South American rainforest. Ignoring the treaty between ZAFT and the Earth Alliance that no fighting would occur in neutral zones, the Dagger Ls attacked and were subsequently wiped out. After this encounter, Courtney met freelance journalist Jess Rabble; after seeing Jess's ZGMF-X12 Astray Out Frame, his thought immediately was "Is that number 12?", referring to the "missing" ZGMF-X12A and adding another unknown to the Out Frame.
Before the beginning of the Second Bloody Valentine War, Courtney is known to have been the test pilot of the experimental XMF-P192P Proto Chaos mobile armor, and later its complete form, the ZGMF-X24S Chaos. When the Chaos is stolen he again pilots the Proto Chaos to fight against a separate group that attacks Armory One. His current position in the Cosmic Era was as pilot of ZGMF-X56S Impulse Unit 03, equipped with a Destiny Sillouette, at the Battle of Messiah. After the war he returns to the Verne Developmental Corp.