What Happened to Jon Seda's Beloved Chicago P.D. Detective Antonio Dawson?

Antonio joined Chicago P.D.'s cast in the pilot ("Stepping Stone") as Intelligence Unit Sergeant Hank Voight's (Jason Beghe) second-in-command.

He had previously in the Vice Squad before being recruited for the Intelligence Unit, and excelled at undercover work.

However, Antonio had already made his first on-screen appearance in the One Chicago universe in Chicago Fire Season 1, Episode 3 ("Professional Courtesy"), in which the sergeant's son Justin Voight (Josh Segarra) got into a drunk driving accident that left a boy paralyzed. Antonio ended up running interference with the CFD members for his boss.

In the pilot of Chicago P.D., he and his then-partner Julie "Jules" Willhite (Melissa Sagemiller) went after a crime boss, Adres "Pulpo" Diaz (Arturo Del Puerto). While in pursuit, Julie was tragically killed right in front of him.

The death of his partner set a haunting tone for the Intelligence Unit.

Antonio was an experienced fighter who ran the training gym for the unit, showing cops old and new the best hand-to-hand maneuvers. According to Voight, Antonio'd had a promising shot at boxing in the Olympics before his time in the CPD.

Antonio's Season 6 departure was the culmination of a season-long storyline.

First, he severely injured his shoulder while pursuing a criminal in Season 6, Episode 3 ("Bad Boys"), and then began abusing painkillers while treating his injury. To satisfy his addiction, he began working with a drug dealer, offering him protection in exchange for pills. But after Antonio's plug got raided anyway, the man's cousin, Jason Rizzo (Sam Pearson), wanted revenge.

In Season 6, Episode 9 ("Descent"), Rizzo kidnapped Antonio's daughter Eva on her way home from college.

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After tracking down Rizzo at an abandoned building, the man made lewd comments about Eva, and Antonio pushed him out a window in a drug-fueled rage. The murder was a shock to Voight, who instantly asked his second-in-command if he was on pills. After Antonio confessed he was, the sergeant and  Adam Ruzek  (Patrick John Flueger) decided it made the most sense for the latter to take responsibility for Rizzo's death, and Antonio was ordered to rehab.

After Antonio returned to the precinct in Season 6, Episode 11 ("Trust"), he regretted allowing Ruzek to take the heat for his actions.

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Internal Affairs opened an investigation into Rizzo's death in Season 6, Episode 21 ("Confession"), and Antonio's shame intensified as the evidence against him grew while Ruzek maintained their cover story. He was last seen relapsing on painkillers in Chicago P.D.'s Season 6 finale ("Reckoning").

In the Season 7 premiere ("Doubt"), the Intelligence Unit visited Antonio's apartment to find it abandoned and in complete disarray. Voight later revealed that he'd taken Antonio to an off-book rehabilitation center.

In Season 7, Episode 3 ("Familia"), the squad learned Antonio had formally resigned from the CPD and moved to Puerto Rico to be closer to family.

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Chi-Hards got a delightful update in Chicago Fire Season 8, Episode 9 ("Best Friend Magic") when Gabby revealed that Antonio was a member of the crisis response team in the Bahamas.

Antonio is the older brother of former Firehouse 51 paramedic Gabby Dawson.

Gabby and Antonio's parents were divorced, but the siblings came from a big extended family and were dear friends during their shared tenure in the franchise.

In Season 1 of P.D., Antonio was married to his wife of then-many years, Laura Dawson (America Olivo). The couple had two kids: Diego (Zach Garcia) and Eva (first Maya Moravec, then Ariana Chantelle Cordero).

After the cartel leader Pulpo kidnapped Diego in Season 1, Episode 2 ("Wrong Side of the Bars"), Laura was devastated and, while Diego was ultimately rescued, she remained concerned about what her husband's job meant for their family. Those concerns intensified after Antonio was shot and seriously wounded by the same man in Season 1, Episode 13 ("My Way").

When Antonio returned to work as soon as he could in Season 1, Episode 15 ("A Beautiful Friendship"), he told Voight that Laura was livid. She wanted him to quit and for the family to move closer to her sister in Crystal Lake, Illinois. 

Laura ultimately left with the kids while Antonio was at work, and he returned to an empty house and a letter on the table

Their tumultuous divorce would played a role in subsequent seasons as the two struggled to acclimate to a custody agreement. 

Eva reacted poorly to her parent's divorce, even running away to see her father at the Precinct in Season 2, Episode 4 ("Chicken, Dynamite, Chainsaw"). She had been worried she'd never see her father again, but Antonio assured her that she, Diego, and him were "a knot" that would never come undone.

She was later seen in the midst of SAT prep in Season 4 of Chicago P.D. and then discussing college application essays with her father in Season 5, Episode 3 ("Promise").

Voight recommended Antonio for the position of lead investigator for the Cook County State's Attorney's Office — which formed the basis of the One Chicago spin-off, Chicago Justice — in Season 4, Episode 16 ("Emotional Proximity").

He accepted the position but returned to his post at the 21st District in the Season 5 premiere ("Reform") having disliked the long-haul cases at the prosecutor's office.

Antonio and Firehouse 51 paramedic Sylvie Brett (Kara Killmer) fell for each other after crossing paths in Chicago Fire Season 5, Episode 3 ("Scorched Earth"), which corresponded with Chicago P.D. Season 4.

She asked him out but he turned he turned down after explaining that his divorce was still fresh and still dramatic. After Sylvie insisted she didn't mind, the two began dating and were together in several subsequent episodes of Chicago Fire.

She also instantly set out to impress his kids, even learning chess to play with Diego, with whom she struggled to connect at first. But after she agreed to look after Diego while Antonio worked a case in Chicago Fire Season 5, Episode 12 ("An Agent of the Machine), his ex-wife Laura showed up at the firehouse in a rage and began shouting insults at the paramedic.

Antonio apologized but became frustrated at Sylvie, noting that he'd warned her about there being drama. She explained that she never expected to be directly attacked, and cut things off between them.

He later visited and apologized for lashing out, but she was still upset by his lack of empathy and stuck to her plan to end their relationship.