Sam Weiss is a bowling alley owner who became involved with the Fringe Division by counseling Olivia Dunham. He seems to be a very intuitive enigma who is able to identify and fix emotional and psychological trauma.
Nina Sharp suggested she visit him because he helped her regain use of her new cybernetic prosthetic arm.
Olivia heads to the bowling alley looking for Sam Weiss. She asks the attendant where he is. He replies Atlanta, Sam met a girl and moved. She starts to walk away. He asks if she's going to give up so easily. He asks if the headaches have started yet, because they will. ("Night Of Desirable Objects")
Sam helps Olivia to tie her shoelaces. She asks Sam how he helped Nina, he said he helped her eat french fries again. Olivia believes she is wasting her time. Sam inquires if Olivia has been sleeping well, as he noticed the circles under her eyes and her pale skin. He guesses it's from the pain of the car accident. He again asks if she has gotten headaches yet, and after her response of no, tells her to come back tomorrow.
Olivia comes back the next day and confirms that the headaches have started. Aggravated, she tells him to cut the Yoda crap. He explains that with head traumas her memories will all "flush out". After she demands "when?", he changes the subject. She stops him and wonders, how is this going to help her. He states, for starters, it will teach you some patience.
After measuring her hand for a ball, he tells her to, again, come back tomorrow. She puts a gun to the back of Weiss' head and yells; "Now you listen to me, you son of a bitch. I am not here to bowl, or to try on shoes, or to have you play games with my head. I am here because I was told that you could fix me." They look towards the bench where she was sitting seeing her cane leaning against it. He plainly says "Take care, Agent Dunham." ("Fracture")
Olivia returns to the bowling alley to thank Sam for his assistance in helping her. He asks, "who died?". They discuss Charlie Francis's death, and to help her cope, he gives her a task.
Sam calls her up while working near a pin setter. He asks Olivia if she collected the business cards from people she met wearing red. He then tells her to circle one letter in every name, both first and last, and to take all those letters and JUMBLE, to find the phrase she needs to hear.
Alone in her car, she finds the phrase "you're gonna be fine", what Charlie told her on her hectic first day. ("Dream Logic")
He later comes to Olivia's apartment and plays a game of Clue with her. ("Olivia. In the Lab. With the Revolver")
Nina Sharp realized that the letters of "Seamus Wiles," "M. Weiselauss", and all the authors of First People books, were anagrams of Samuel Weiss. When she confronted him at the bowling alley, Sam explained to her that he was not Nina's problem, but instead, Peter Bishop was. He told Nina that The Vacuum could be used to create or destroy. Peter Bishop, being uniquely tuned to operate it, will determine how the the machine reacts. Weiss, when pressed for more, revealed that whichever universe he is most in tune with will be the one that survives. A determining factor in this frequency, he continued on, was which Olivia his heart belonged to. When deciding who he was in love with, Peter would also decide which universe he chose. When Nina said she was not worried about Peter's choice, claiming he would obviously choose the Olivia he had known for years, Sam cryptically replied that he wasn't so sure.("Concentrate and Ask Again")
He is seen looking at a newton's cradle ticking on its own. He goes on the run and disappears. Nina Sharp tells Olivia to find him and that he is an expert on the doomsday machine. He eventually bumps into Olivia and says "We don't have much time" He tells Olivia about a case that holds a crow bar that will open the doomsday device for Peter. He has the case, but it requires a key to open the case, which he does not possess. He then assists Olivia in finding the key. After they find the key, the security system engages and he stops the exterior gates from locking them in by rolling a ball into them. He then states, "Hey, I work in a bowling alley." He and Olivia then open the case up to discover that the crowbar is Olivia. This shocks both of them. He then expresses a wish to see the doomsday device, but Broyles tells him "This is where you get off." He then watches Liberty Island from a port. ("The Last Sam Weiss")
In the year 2036, Sam's body is found in a forest, slumped over a truck's steering wheel. Oliva identifies the body as Sam's through his wallet and driver's license, which are still on him. Around his body there are two Observers and one Loyalist, dead as well. Apparently, Sam was trying to protect the signal from interruption, as he was recruited by Donald. Based on the state of decomposition of the body, Olivia believes he has been dead for 10-15 years. She also states that they didn't know Sam from this timeline, but from the Original Timeline. Astrid wonders if he was, in fact, Donald which Olivia denies since he doesn't share features like hair color and body complexion. ("Black Blotter")
Although not seen in the Final Timeline, Sam Weiss would still be alive in 2015, as he had lived to fight the Observers in the Alternate Timeline. Because the Final Timeline had only overridden the Alternate Timeline beginning at 2015, Sam Weiss would still be alive.
- In "Over There: Part 2," at the Alternate Universe's Harvard Lab, a blackboard is briefly shown. On this blackboard is the phrase "A Demon's Twist Rusts." This phrase can be anagrammed to say "Don't Trust Sam Weiss." Also, the Cypher from this episode spell out "W-E-I-S-S".
- His name is a play on Samwise, the first name of Frodo Baggins' trusty sidekick in the Lord of the Rings series.
- Erich Weiss was the real name of Harry Houdini. J.J. Abrams named one of the detectives Eric Weiss in Alias.
- He didn't meet either Olivia or Peter in the Alternate Timeline, but he seemed to be a part of the Resistance against the Observers Invasion.