Thaneespi was a member of the Mon Calamari species and a participant in the fleet belonging to the Alliance to Restore the Republic. In the year 4 ABY, Thaneespi held the position of first officer aboard the MC80A Home One Type Heavy Star Cruiser named Home One. He was present at a meeting that took place shortly before the Battle of Endor. Before the meeting, where they discussed the Alliance's plan for the Forest Moon of Endor, Thaneespi had a brief discussion with Admiral Gial Ackbar.
Home One then made its way to Endor, where Thaneespi took on the role of one of the commanders of the Alliance's Star Cruiser during the battle that unfolded there. This battle led to the destruction of the Galactic Empire's second Death Star and the death of the Emperor Palpatine. Thaneespi's skin featured a brown-mottled pattern, and he had yellow eyes. He was seen wearing a helmet along with a beige-colored uniform.
Thaneespi's initial appearance was in the 1983 original trilogy film, Star Wars: Episode VI Return of the Jedi. His identification in the new Star Wars canon occurred in the twenty-fourth issue of the De Agostini's Star Wars: Build the Millennium Falcon magazine series, around June 17, 2015. Within the Star Wars Legends storyline, Thaneespi's name was first revealed through the Death Star II Limited expansion set for the Star Wars Customizable Card Game, which was released in 2000.
The filming of the scenes aboard Home One took place during the week starting on Tuesday, February 16, 1982. The helmet that Thaneespi wore was originally meant for Admiral Ackbar, but it was given to Thaneespi instead because Ackbar's articulated head would have made wearing the helmet difficult. Pete Ronzani's team was responsible for the design of the helmet.