Zekk was born on the planet Ennth and lived there with his parents for the first eight years of his life. He was separated at birth from his twin sister, Ingvor, although they were reunited twenty-two years later.
At the age of eight, Zekk barely escaped the volcanic eruptions and other cataclysms that rocked the planet Ennth, and his parents both died. He lived in the underlevels of Coruscant for many years, eventually being captured by the leaders of the Shadow Academy and later joining the Jedi Academy with the Solo twins, Jaina and Jacen.
In 26 ABY, the Stellar Imperial War began. During this war, in 28 ABY, Jacen and Anakin Solo disappeared on a mission and were assumed to be dead. Zekk spent much of his time on the planet Yavin VIII, helping to safeguard some of the younger Jedi trainees. Jaina joined him there, and the two of them briefly captured Lord Welk, whom Zekk had known from the Shadow Academy.
Jaina began to fall to the Dark Side, and Zekk chased her down, all the way to Empress Shira's Stellar Imperial headquarters on Cyalax. He was unable to convince Jaina to return to the Jedi, and did not see her again for several months, when the remnants of the Jedi Order gathered on Hapes.
He was there for her when she caught a flicker through the Force that Jacen was still alive, and fought at her side during the final battle, the Battle of Angwel, in 29 ABY.
Less than a year after the war's end, Zekk married Jaina. They had two children, a daughter Nilla and a son Verayan. Ingvor reappeared at the wedding, and remained in contact with the family from that point forward, but she and Zekk were not close enough for him to bail her out of the financial trouble she often found herself in, especially when she refused to train as a Jedi and kept living on the edge of the law.
Zekk was injured by Boba Fett in 43 ABY, when the Jedi attempted to prevent him from assassinating Queen Mother Tenel Ka. Boba was killed in the fight, but he did kill Tenel Ka first. Zekk recovered fine from these injuries, and lived out the rest of his life with Jaina near Coruscant.