I completely forgot that this Star Trek: The Next Generation actress appeared in two episodes of Star Trek: Deep Space Nine. Many actors portrayed multiple roles within the Star Trek franchise, often remaining unrecognizable due to alien makeup, different costumes, or vastly different characteristics and personalities.
Susan Gibney From Star Trek: The Next Generation Also Appeared In DS9
Susan Gibney Portrayed Dr. Leah Brahms On TNG & Commander/Captain Benteen On DS9
In Star Trek: The Next Generation, Susan Gibney portrayed both the real Leah Brahms and the hologram version of her brought to life by Geordi La Forge (LeVar Burton). In TNG season 3, episode 6, "Booby Trap," Geordi worked with the holodeck's recreation of Dr. Brahams to work on the Enterprise-D's engines.
In one of TNG's most cringeworthy storylines, Geordi developed feelings for the holodeck version of Dr. Brahms, making his eventual meeting with the real Brahms in "Galaxy's Child" extremely awkward.
Susan Gibney's next Star Trek role came in Star Trek: Deep Space Nine season 4, episode 11, "Homefront," in which she plays Starfleet Commander Benteen. After a suspected Changeling attack at a diplomatic conference, Captain Benjamin Sisko (Avery Brooks) travels to Earth to help Starfleet implement new security measures.
Upon arriving at Starfleet Headquarters, Sisko meets with Admiral Leyton (Robert Foxworth) and his adjutant, Commander Benteen. In the second part of this two-parter, "Paradise Lost," Leyton promotes Benteen to captain and gives her command of the USS Lakota.
Captain Sisko and his crew eventually discover that Leyton is planning a coup d'état against the United Federation of Planets. Upon learning that the USS Defiant was traveling to Earth with proof of his duplicity, Leyton ordered Captain Benteen to destroy it. Benteen, however, stood down after hearing Sisko explain Leyton's deception.
Commander Benteen In DS9 Was A Very Different Character From TNG’s Dr. Leah Brahms
Brahms Was A Scientist, While Benteen Was A Starfleet Officer Through & Through

Although both of Susan Gibney's Star Trek characters were humans, it's not immediately obvious that they are portrayed by the same actress. For one thing, there were several years between Gibney's appearance on TNG and DS9, and, somehow, putting her in a Starfleet uniform and giving her a different hairstyle made her almost unrecognizable.
Plus, Leah Brahms and Captain Benteen are very different characters. Brahams is a scientist who is passionate about her work, which includes designing parts of the Galaxy-class ship's warp drive engines. Benteen, on the other hand, is a serious and by-the-book Starfleet officer who implicitly trusts her superior, Leyton, which almost costs her her career.
In her appearances on Star Trek: The Next Generation and Star Trek: Deep Space Nine, Susan Gibney made Dr. Leah Brahams and Captain Benteen distinct and interesting characters who played significant roles in their respective stories.