Gabriel Lawrence is portrayed by Ignacio Serricchio, he is Melinda's Step-brother and like Melinda, he possesses the gift to talk to the dead too.
When he was a child, Gabriel knew he could interact with the dead, but nobody believed him, and he received psychiatric treatment in a mental health institution. Gabriel never had a living friend. In fact, all of his friends were dead, and he always hated watching them cross over into The Light. He managed to get out of the mental health institution by lying. He was in the same mental health institution where his mother also resided.
In "The Collector", Gabriel is now in his late twenties, and he had recently moved to Grandview. He mentions that Grandview always brings him memories. Melinda has the opportunity to meet him, and she is amazed by the gift they have in common. Melinda warns Gabriel about a shift in the "other world": ghosts are becoming stronger. She tells him how she struggled against a very dark spirit called Romano the year before when a plane crash occurred in Grandview. However, Melinda discovers that she was so naive to believe in Gabriel, who had invited her to work with him in the difficult task of dealing with ghosts. Gabriel turns out to be a Ghost Whisperer from the Dark Side, and he had been gathering souls to get prepare for what "was coming", a complex prophecy of the death of a "loved one".
In "Weight of What Was", Gabriel returns to Grandview and visits Melinda at her home. She isn't too happy to see him, and neither is Jim, which is understandable. Jim tackles him to the ground when he first sees him. Though Gabriel has come to see Melinda about their father, he leaves an envelope with her which is filled with photos and some belongings from their father, such as a locket which has a photo of a baby that fits inside. Later in the episode, Gabriel has a conversation with Melinda and she asks him about a spirit that has visited her, she believes this spirit is his mother though Gabriel later confirms that it's not. After being tipped off by Scott, the spirit from the archives, Gabriel locks Melinda in the underground tunnels when she goes inside, seeking answers about the large amount of deaths in Grandview during the 1800's. Gabriel later has a conversation with his deceased father who talks about getting Melinda on "their side" and the father seems angry that Gabriel almost killed Melinda because it wasn't part of what he had asked Gabriel to do.
Gabriel also appears in "All Ghosts Lead to Grandview" where he has a brief conversation with Melinda about a young Ghost Whisperer named Becca. After leaving Grandview, he later returns in "Stranglehold" where he is seen staying at a hotel where his and Melinda's father Tom Gordon has been seeking refuge, His current whereabouts are unknown. At the end of season three, we then find out that Tom isn't her real father, making Gabriel, not her real brother. He was only using her to try to get her to join the dark side.
Mediumship: He also can see and communicate with spirits like Melinda Gordon.
Gabriel makes a total of 6 appearances throughout the first three seasons.