Gabriel was a stern but loving father, who had high expectations for his two children. He was proud of Simon's work as an exceptional doctor and supported River's choice to attend an Alliance-funded academy for the extremely gifted. Gabriel and his wife were completely blind to the changes in River's personality as revealed in her letters to the family. He refused to believe Simon's idea that she was communicating in a hidden code to get help. When Simon was arrested for being in a "blackout zone", he bailed out his son but sternly warned him never to disobey him again. Simon cut himself off from his parents permanently and then carried out a very dangerous rescue for his tortured sister without any help from Gabriel or Regan.
Gabriel Tam was portrayed by William Converse-Roberts.