Delenn was born in 2202, into the family Mir, a Religious Clan on Minbar. After years of training and study she was chosen to be an acolyte to the Grey Council and the apprentice of their leader Dukhat. A misunderstanding between her ship and a human vessel caused the humans to attack and Dukhat was killed. Filled with rage, Delnn and the Council voted to destroy all humans.

After nearly three years of fighting, Delnn discovered that the human Jeffrey Sinclair had the soul of the most significant figure in Minbari history, Valen. This allowed her to convince the council to end the war.

In 2256, Delenn came aboard Babylon 5 as an ambassador. Delenn used a triluminary to build a cocoon for herself and emerged as a Human-Minbari hybrid. She met; fell in with and married John Sheridan. Delenn was instrumental in the formation of the Interstellar Alliance. Sheridan was elected president but when he retired Delenn took the position.

After 20 years together, and one son named David, Sheridan passed away. Delenn continued serving as President for many years until finally stepping down and withdrawing entirely from public life. Delenn's ultimate fate and jorney remain unknown.