Ivanova joined Earthforce after her brother died in the Earth-Minbari War - she gave him her right earring as a good luck charm and has not worn it ever since (In the Beginning).
She was assigned to Babylon 5 in 2258 after the departure of original 2IC, Laurel Takashima. Shortly afterwards, her father, Andrei, died of an illness (Born to the Purple). Her mother, Sophie, had died some years before as a result of taking telepathy-suppressing drugs (Midnight on the Firing Line), and as a result Susan is wary of telepaths and Psi Corps - as a latent telepath herself she does not wish to suffer the same fate (Eyes, Divided Loyalties).
She was promoted to Commander by Captain Sheridan, with whom she had served previously, and her first task in this position was to settle an ongoing Drazi ritualistic rivalry (The Geometry of Shadows). She developed a brief relationship with Talia Winters despite her mistrust of telepaths (Eyes, A Spider in the Web) which was brought to a sudden halt (Divided Loyalties). Afterwards, she has the affections of Ranger Marcus Cole to contend with (Exogenesis, Shadow Dancing), even though she doesn't reciprocate.
She managed to recruit the remaining First Ones in the war against the Shadows (Voices of Authority, Into the Fire), and her expertise in providing news reports about the Shadow conflict (Falling Toward Apotheosis) made her perfect for providing "the Voice of the Resistance" to counter President Clark's propaganda (Lines of Communication, Conflicts of Interest).
When Sheridan was captured by Earthforce, Ivanova took command of the fleet in the campaign against Clark (The Face of the Enemy) where she was severely injured in battle (Between the Darkness and the Light). To save her life, Marcus was prepared to give his own (Endgame).
Saddened by Marcus' sacrifice, she was subsequently promoted to Captain and given command of her own ship for a year-long tour of duty (Rising Star). She eventually becomes an Earthforce General, before Delenn asks her to fulfill the position of Entil'Zha after Sheridan's passing (Sleeping in Light).
Played by Claudia Christian, who appeared in the films Mad About You and Maniac Cop II, among others, and in the Quantum Leap episode Play It Again, Seymour. A mix-up with her contract deadline with Warner Bros prevented her from returning for the fifth season.