Four seasons, three bosses for special agent Tom Baldwin on the hit-series “The 4400.”

This season, the reigns of command at the National Threat Assessment Command (NTAC) will be taken by Meghan Doyle, played by Australian actress, Jenni Baird. Baird is a new addition to the regular cast.

Doyle follows in the footsteps of the previous NTAC commanders, Dennis Ryland played by Peter Coyote and Nina Jarvis played by Samantha Ferris.

“They liked Peter Coyote quite a bit,” said executive producer, Ira Stephen Behr. “I thought Peter was kind of phoning it in when he was doing the head-of-NTAC thing. It’s only after he left NTAC and became Dennis Ryland, the man who’s trying to save the world from the 4400, that the character became interesting. But so they always felt that Nina Jarvis was neither fish nor fowl. And that’s kind of our fault, because we kept saying we were going to do all these stories, give her all these interesting character quirks, and she kept being the finger-pointer. We never were able to develop the stories we wanted to. It always was the one-note finger-pointer kind of thing. And then they said, ‘You know, we really want someone with some more sizzle.'”

Enter Meghan Doyle, who makes her first appearance in the fourth-season premiere “Wrath of Graham” as a Fellini-loving, rule-breaking outsider who threatens to upset the careful order of the quasi-law-enforcement establishment of NTAC.

And it’s no accident that Doyle is an attractive blonde. “I had the bright idea that Meghan, this new character, could give us a new head of NTAC and would also give us someone for Tom to ultimately get involved with, because, goddam it, we’re going to make a romantic pairing on this show work if I have to go in there and do it myself,” Behr said