In October 2016, Seda confirmed that the character would move to the third spin-off Chicago Justice, debuting in March 2017, after resigning from his position in the CPD to take up a job with the State's Attorney's Office.

[2] After the cancellation of Chicago Justice, the character is written to have returned to the CPD due to his frustration with the bureaucratic red tape he often encounters.

The custody issue was never fully explained on the show; the children live with their mother, and Dawson keeps in touch with them by phone.

The character is frequently seen on Chicago Fire and was first introduced in the episode "Professional Courtesy" after Gabby and her colleagues from Firehouse 51 rescue a boy and his father in a car accident caused by a drunk Justin Voight, Hank's son.

He was partnered with Detective Julie "Jules" Willhite, with whom he shared a close friendship until she was killed by drug lord Andres "Pulpo" Diaz in "Stepping Stone.

He has been involved in numerous sting and undercover operations, some of which include drug busts, high-profile arrests, and more personal cases.

At the end of "An Agent of the Machine," Antonio breaks up with Sylvie after she confronted him about the fight between her and his former wife Laura when she showed up at the firehouse to pick up her son.

When Pulpo, a Colombian drug lord is arrested, Diego is kidnapped by a man named Mateo.

[7] He also worked with Trudy Platt, now the desk sergeant at the 21st District, during his patrol years and saved her life when she was shot by pulling her out of the line of fire.

[8] In "Chicken, Dynamite, Chainsaw", in the locker room at the end of the shift, Sean Roman tells him about his security business.

During the course of these episodes, it was shown that Roslyn's wife, Layla, was flirting with and trying to seduce Dawson, but he turned down her advances.

In "300,000 Likes" Antonio is offered a job as lead investigator at the State's Attorney's Office, which he accepts in the next episode, "A Shot Heard Around the World".

In "Promise", with Dawson back in Intelligence, he takes on a case that involves the brutal murder of a young Latina woman who is suspected to be a drug mule for a drug cartel after he and his daughter Eva came up on a crime scene and his daughter overheard an officer at the scene throw out a racist comment with regards to the victim in which he takes it personally.

While searching the victims' apartment, Burgess and Atwater find her young son hiding in the closet.

Burgess finds the victim's sister, who at first refuses to cooperate, fearing for her safety, until Antonio promises her protection.

The kid recognizes that the van was there the night his mother disappeared and that the description matches another employee, Frank Lopez.

He tells a totally different story, saying Marcella called him 2 months ago about El Lobo, not just the day before.

In "Homecoming", his loyalty came into question when he sees an inmate that was responsible of killing Olinsky, severely beaten and left bleeding on the floor.

Though Antonio does find a gun, two witnesses immediately exclaim that Voight shot the man "in cold blood."

In the Season 6 premiere "New Normal," directly following the rattling death of Alvin Olinsky and the events after, Voight is put under investigation, leaving Antonio in charge of the unit.

When Antonio answered truthfully about what he saw to the Police Board, he was unable to be of any help to Voight in clearing his own name.

Antonio was left taking the fall for the actions of Ruzek and the team, though no actual issues are mentioned.

In the later episodes, which may have occurred following a time lapse, the two no longer show ill will toward one another, although Ruzek's rebellious nature is still a compromise.

It was confirmed in "Descent" when he ran out of a known drug house that was being raided by Intelligence and was eventually caught by Burgess, lying about his involvement.

Dawson beats the kidnapper as punishment, and when he jokes about her age to aggravate him, he pushes him out the window to his death.

Voight, having found out about Antonio's painkiller addiction, advises him to seek a rehab facility, while Ruzek covers for his mistake in "Brotherhood."