Guest Star: Brian Thomas Smith

Brian Thomas Smith

Brian Thomas Smith is an American actor best known for his recurring role as Zach Johnson on The Big Bang Theory.

His TV credits include roles on shows including A Good Knight's Quest, Casual: The Series, and The Flip Side. He has had recurring role on TV shows such as The Indies, Wolfpack of Reseda, Suit Up, and The PET Squad Files. His TV credits also include guest appearances on Two and a Half Men and Happy Endings.

You are viewing a list of Brian Thomas Smith's 9 appearances on The Big Bang Theory.

  • The Lunar Excitation

    Season 3, Episode 23 - The Lunar Excitation
    Aired May 24, 2010

    When Leonard goes to invite Penny to come see the guys' experiment on the roof, she is with a new guy, Zack, who she met at the Cheesecake Factory. After Zack asks some dumb questions, even Sheldon claims Penny could do better.

    Appeared as Zack

  • The Alien Parasite Hypothesis

    Season 4, Episode 10 - The Alien Parasite Hypothesis
    Aired December 9, 2010

    When the girls run into Penny's ex, Zack, during a girls' night out, Amy is overcome with new sensations which she struggles to understand. Sheldon helps Amy come to terms with her sexual feelings for Zack, encouraging her to follow her endocrine system.

    Appeared as Zack

  • The Justice League Recombination

    Season 4, Episode 11 - The Justice League Recombination
    Aired December 16, 2010

    After the guys hurt Zack's feelings, they try to make things up to him by taking him to the comic book store. The guys then decide that Zack would be the perfect addition to their Justice League group for the upcoming New Year's Eve costume party.

    Appeared as Zack

  • The Toast Derivation

    Season 4, Episode 17 - The Toast Derivation
    Aired February 24, 2011

    When Sheldon refuses to hang out with his regular group of friends at Raj and Priya's apartment, he forms a new social group including Penny's ex-boyfriend, Zack.

    Appeared as Zack

  • The Thanksgiving Decoupling

    Season 7, Episode 9 - The Thanksgiving Decoupling
    Aired November 21, 2013

    Penny and Leonard's Thanksgiving is thrown into disarray when Penny realizes that her "fake Vegas wedding" to her ex-boyfriend Zack is actually very real. Zack visits the guys as they spend Thanksgiving at Mrs. Wolowitz house so he can sign the annulment papers.

    Appeared as Zack

  • The Cooper Extraction

    Season 7, Episode 11 - The Cooper Extraction
    Aired December 12, 2013

    When Sheldon flies back to Texas for his sister's childbirth, the gang gather to decorate the apartment's Christmas tree. When they begin to wonder what life would be like without Sheldon, they come to realize how big a part of their lifes he has become.

    Appeared as Zack

  • The Fermentation Bifurcation

    Season 9, Episode 22 - The Fermentation Bifurcation
    Aired April 28, 2016

    When the gang run into Penny's old boyfriend Zack, he makes Leonard and Howard worry about the military applications of their guidance system, and causes trouble for Raj's relationships.

    Appeared as Zack

  • The Cognition Regeneration

    Season 10, Episode 22 - The Cognition Regeneration
    Aired April 27, 2017

    When Leonard and Penny run into her ex-boyfriend Zack, who is now happily married, he offers Penny a job.

    Appeared as Zack

  • The Bitcoin Entanglement

    Season 11, Episode 9 - The Bitcoin Entanglement
    Aired November 30, 2017

    When they guys remember mining valuable Bitcoin on a laptop that Leonard gave to Penny, they turn to her ex-boyfriend Zack to try find their digital fortune.

    Appeared as Zack

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