Justin Walker is the fifth of the Walker siblings and army veteran. He is portrayed by Dave Annable.
He is divorcee to Rebecca Harper. Justin became a paramedic in the fifth and final season, in which he also turned 30 years old in. After Rebecca and Justin got married in the fourth season, and after Holly Harper, Rebecca's mother, fell victim to memory loss, Rebecca filed for a divorce when Justin returned to the army for a third and final time. During the fifth season, Justin also had multiple relationships after Rebecca, and in the last episode, he was in a relationship with a woman who was in the process of getting divorced named, Tyler. The two of them actually dated in the first season as well.
In the first season, when Justin returned from the army after his first time, he got a drug problem, which was healed throughout the season.
Justin's relationship with Rebecca was complicated, and began with them both thinking Rebecca was William's (Justin's father) daughter. But, it turned out, Rebecca's father was David, a man who Holly rekindled with.
At the beginning of the season Justin clearly had issues mentally. He was on drugs the day his dad died so he was numb to feelings but that didn't stop him from getting to the pool and trying to save him. He had problems keeping jobs whether it was not showing up or getting high while working, when his brother Tommy got him a job as a bellkeep he began to change impressing his family. First when Paige was fussing over having her insulin Justin rushed to her and gave her the injection while distracting her with silly faces the taking her to the table to eat while the rest of the family stood around in shocked. He simply explained that it was his army training that caused him to help, when he went to get Paige a drink Kevin said "Who was that masked man?"
In episode 7 Justin made a real break through, he was dating Tyler (His boss but not for the reason you would date a boss), then he confronted his brother Tommy he explained why he was on the drugs and how he was scarred from what he couldn't do in the army.
In episode 8 Justin was happy with Tyler until he had been stoplossed by the government and was ordered to return to the army, unable to cope Justin turned back to drugs and stopped attending work causing Tyler to fire him and end there relationship. Throughout the episode flashback occurd showing how Justin decided to join the army, it wasnt Kitty fault it was Nora Justin wanted to join the army like his dad did. Later he heard Nora saying he not strong enough to do this lighten his flame to want to do it more. By the end of the episode Tommy, Nora and Kitty found Justin unconsious in his flat barely alive.
In episodes 9 and 10 Justin came to terms with having to return while Kevin worked hard to keep him home, throughout the episodes a court case ensued were Justin was question on his family, his life and his drug addiction but the end the Judge told Justin he was to return. While Kevin was comforting a sad Justin a Sargeant came up to them and told Justin he has six month until he has to return, when Kevin asked the sarg. why he changed his mind and why know he simply said."I had a brother too once"
In episode 13 Justin was released from rehab to attend his mother 60th birthday party with the expectation that no alcohol would be in his reach. At the party, Justin snuck away to speak to Tyler only to discover she was happy and already in a new relationship. Since everyone had hidden the alcohol in Kitty closet so Justin couldn't be tempted by the end of the day Sarah, Tommy and Kevin were getting drunk when Justin walked in proving he clearly can handle being around alcohol and begins to have a laugh again like old times.