Justin Tighe was a Human male and a member of Starfleet holding the rank of lieutenant in 2357.
Tighe was born in 2327 on Klatus Prime, a planet in Sector 22309 that was home to a small mining colony. Conditions on the planet were harsh and his family barely had enough food to live on. His family had lived there for generations, but Tighe decided to leave the colony and seek his own way at the age of ten.
In 2355, Tighe was captured by Cardassians and tortured for three days. He managed to escape and make his way back to Starfleet forces.
In 2357, Lt. Tighe was a member of the science team on the USS Icarus on the Arias expedition. He was also a member of the Rangers, an elite squad of Starfleet personnel who were secretly part of the mission so that they could gather intelligence on the Cardassian military.
Six months into the mission, Admiral Owen Paris and Ensign Kathryn Janeway were captured by the Cardassians. Within a short time, the group of Rangers, led by Tighe, rescued Paris and Janeway. As they were leaving the compound, Tighe tripped on a root and broke his ankle. Janeway stopped to help him and together, they were able to survive the attack of a Toskanar dog and a Cardassian soldier long enough to be transported away. They started dating soon after this incident.
By 2358, Tighe and Janeway were engaged to be married. That year, Tighe was test piloting the prototype ship Terra Nova that Edward Janeway had been working on designing for the past two years. While flying to the Tau Ceti system with Edward and Kathryn Janeway on board, the ship crashed into an iceberg. Kathryn Janeway survived, but Tighe and Edward Janeway were killed. (VOY novel: Mosaic)
In 2375 aboard the USS Voyager, Janeway told Chakotay about Tighe. She believed that because she loved Chakotay in the same way that she had loved Tighe, she could not bear to lose him and so it was impossible for the two of them to become romantically involved while she was responsible for his life. (VOY short story: "Isabo's Shirt")