The character was initially introduced in Chicago Fire as a dirty cop who tries to cover up for his son and uses all means necessary to do so, including threatening Lieutenant Matthew Casey, one of the protagonists of Chicago Fire. Voight's circumstances were eventually clarified with the creation of the spin-off Chicago P.D. However, he has a well-documented feud with Casey as a result of what happened between them and his interactions with the firefighters of 51 is marked by tension and suspicion, despite the fact that he manages to earn their grudging respect for his dedication to seeking justice for victims.
Hank has a son named Justin whom he bails out in "Professional Courtesy" after he crashes into a van while under the influence of alcohol. As the result of Justin's recklessness, the boy (Mike Duffy), who was in the van, is paralyzed from the waist down stopping him from playing hockey ever again. This incident marks the beginning of the tension between Hank and Lieutenant Matthew Casey.
Hank is widowed; his wife Camille died six years prior to "Now I'm God" of ovarian cancer. Hank's father, Richard, was also a Chicago Police Officer.
This character was first seen in Chicago Fire as an antagonist. Voight's ruthless methods cause friction with Lieutenant Matthew Casey, a firefighter at the nearby Firehouse 51. Casey had arrived on the scene of a serious car crash where the driver, Voight's son Justin, had been drinking. The resulting arrest would have been a DUI with possible repercussions as the passenger in the other car had been paralyzed from the waist down. Voight had tried various methods to stop Casey from filing the report against Justin. First beginning with bribery (a new television set for the CFD) and escalating to physical threats towards Casey and his then-fiance, Dr. Hallie Thomas. Voight attempted to have Casey injured or killed, but was arrested by Detective Antonio Dawson in a sting. While in prison he offers Gabriela Dawson information on who shot Antonio, who was working undercover at the time. This was in exchange for a future favour, which Dawson reluctantly accepted. Internal Affairs (I.A.) later released Voight from prison and promoted him to Sergeant of the Intelligence Unit at CPD. Voight began working with Dawson and Detective Juiliet "Jules" Willhite to investigate a series of murders relating to pharmacy nurses. The case was related to a drug dealer named Thomas Cobb whom Voight killed to protect Casey. Unfortunately, Hallie was murdered after accidentally discovering a drug operation at the hospital she worked at.