Johnny was born premature. When Johnny, Lee and Nancy were kids and they fought, Mick and Linda would take them swimming to calm them down. As a kid, Johnny loved watching the TV series "Ally McBeal", Linda used to let him stay up late every Thursday night to watch it. When Johnny was four, Johnny tripped and hit his head off a iron coffee table that Mick had found in a skip.
Linda finds it extremely difficult to come to terms with Johnny's sexuality, which leads to numerous arguments with Mick and Shirley. Johnny eventually reveals his sexuality to Whitney, who is hurt as she feels that Johnny has been using her. She soon forgives Johnny and even offers for him to move in with her and her family if his relationship with Linda does not improve. Johnny later threatens to leave The Vic, so Mick forces Linda to sort things out. Linda seems to have finally come round to the idea of Johnny being gay, but she later breaks down over the situation. Johnny realises that Linda is not fully accepting of his sexuality when she invites Whitney (who she thinks is pregnant) over and tries to set them up, Johnny feels hurt and betrayed and a huge argument ensues. Mick then tells Linda to fully accept his sexuality or risk losing him forever. Whitney tells Johnny that he needs to get a boyfriend so that everyone can accept it and move on with their lives, As a result of this Nancy and Whitney sign Johnny up for internet dating. The New Year saw Nancy, Johnny's sister, return to the family.
Clearly delighted by this, little did Johnny know that his secret of being gay was about to be revealed. During a heated argument with Linda, Nancy let the cat out the bag and revealed that her brother was gay. Quick to retract what she'd said, suspicions arose, leading to Johnny and Mick having a heart to heart. Telling him that he would love him no matter if he was gay or not Johnny broke down in tears revealing the truth about his sexuality. Little did Johnny know that his mother had overheard the entire conversation... Would she be able to accept her son's sexuality? And if the situation was not already uncomfortable enough, Tina and Auntie Shirl made it their priority to rock the boat with Linda all the more. And what better way than to persuade Johnny to attend the launch of a new local gay bar? Uncomfortable, but agreeing to go, Johnny was shot down by Linda... He had to work that night. Poor Johnny! Linda continued to argue and deny that Johnny is gay. Finally admitting to Whitney that he is gay, the two launched a plan to make Linda see sense, and make up with Johnny. With the plan cued, Johnny returned home to break the news that he was moving out, which soon prompted Linda to admit her true feelings and finally make up with him.
With peace restored, the next logical step for Johnny was to find a boyfriend. With Nancy launching his online dating campaign Johnny began talking to the ‘Walford Wonder’. However, he was soon shocked when he discovered the Wonder’s true identity. Johnny later starts university, studying to become a lawyer but failed two of exams and this Linda went to see his tutor behind his back to try and get his marked changed. Johnny was furious about this and embarrassed her by telling her to sing on the karaoke, when he knew she had a bad voice. He later has a massive row with Linda and then decides to leaves walford. Linda then convinces Johnny to come home but on their way they stop off at London's Gay Pride event were Johnny meets Gianluca Cavallo. Gianluca and Johnny fall in love and soon head to the Queen Vic and have sex - when Johnny loses his virginity. When Gianluca announces he is going back to Italy, Johnny considers moving with him, however, decides to stay in London, with his family. Months later, in December, Gianluca arrives back in London and, although he doesn't appear on-screen, Gianluca asks Johnny to go traveling with him.
Johnny agrees and contacts his university and is given permission to go on a gap year. Johnny leaves Walford on December 23rd 2014. Two days later, on Christmas Day, Johnny makes a video call via Skype to Linda to wish her a happy Christmas - this was Strike's final appearance in EastEnders. In early 2015, when Lee and Nancy and Amelia discover that Linda was raped, the family decide against telling Johnny about Dean's wrongdoing, as they wouldn't want to upset him on his travels.
In an episode dated 15 April 2016, Johnny stated, whilst he was in Italy, Johnny woke up in hospital one night in Venice. Johnny and his friends got drunk and stole a gondola and took it out on the Grand Canal. Johnny stood up and sung "Just one Cornetto". He then smashed his face on a bridge and got knocked out. Whilst in Italy, Johnny took an internship at a British NGO in Rome. In an episode dated 12 April 2016, Johnny stated that he loved Gianluca Cavallo so much, moving out to Italy, he barely knew Gianluca. But everything was so exciting, so new. When Mick and Linda visited Johnny in Italy, Johnny and Gianluca hid that they were having relationship problems. In the end, Gianluca and Johnny wanted different things. Gianluca moved out back to his ex. Gianluca’s mother wanted Johnny to stay with her but Johnny decided to go home after he had a call from Mick, to surprise Linda.
Johnny returned from Italy on 11 April 2016, now played by Ted Reilly, and Linda is happy to see him. He confesses he has broken up with his boyfriend Gianluca. The family later decide to tell him about the rape.
During the fallout after the Willmott-Brown reveal, Mick calls James in for a word in the Queen Victoria. The Carters tell him they want the money they paid Weyland & Co back. Johnny tells him he won't have a leg to stand on if it goes to court. James tells him his legal team have been working overtime to figure out why some of the signatures on the Weyland & Co documents differ, and says it suggests forgery.
Ted Reilly (who plays Johnny Carter) announced his departure from the soap on the 19th December 2017. This comes after a huge cast shake-up which was announced in October, with the departures of Abi and Lauren Branning, Ben Mitchell and Sophie Willmott-Brown, along with the reintroduction of characters Masood Ahmed, Woody Woodward, Melanie Owen and Tiffany Butcher. A spokesperson for EastEnders said: "We can confirm Ted has finished filming with EastEnders and wish him all the best for the future".