Matthew Ross
Matthew Ross (Garret Dillahunt) is a lobbyist in the Collier organization who joined The 4400 to advise Shawn Farrell after Jordan Collier's death. Ross was intent on carrying out Jordan's plans for The Center, even if it required manipulation and working against The 4400s themselves. Ross is just as ethically gray as his predecessor ... and as driven.
His objectives are still somewhat unclear to those around him, including his unknown and seemingly questionable intentions towards Isabelle.
SEASON THREE TIMELINE
Being Tom Baldwin
Showering Isabelle with gifts (in what almost seems like a bribe) Matthew attempts to give Isabelle advice on how she should proceed with Shawn.
The New World
Matthew returns to The 4400 Center after finding it difficult to lobby on behalf of the NOVA Group
Infuriated by her recent suicide attempt, Matthew visits Isabelle, telling her exactly who she is and what the future's plans are for her.
Matthew has a strange phone conversation about someone "being back" only to be interrupted by Isabelle. He gives her a syringe of white liquid, explaining that if she uses it, it is the only thing capable of killing her.
SEASONS ONE AND TWO TIMELINE
With Shawn in danger of being overwhelmed by his 4400 Center commitments, Matthew arrives to get The Center in order. It's clear from the beginning that Matthew intends to govern the day-to-day operations of The Center and manipulate the direction it ultimately takes.
Richard and Lily discover Ross and his team of doctors performing tests on Isabelle. While Lily is infuriated, Ross has an easier time convincing Richard, explaining that Isabelle's brain functions exceed those ever thought capable by a human being.