Kevin Sussman as Stuart Bloom (recurring seasons 2–5, 7, starring seasons 6, 8–12): A mild-mannered, under-confident owner of a comic book store. A competent artist, Stuart is a graduate of the prestigious Rhode Island School of Design, and though he is socially awkward he possesses slightly better social skills. Stuart implies he is in financial trouble and that the comic book store now also is his home. He is later invited to join the guys' group while Howard is in space. Stuart gets a new job caring for Howard's mother later. After Mrs. Wolowitz's death, Stuart continues to live in her home, along with Howard and Bernadette, until he finds a place of his own.
Bernadette's due date arrives but she still hasn't given birth. As Amy and Howard work together at the college, the rest of the friends try various ways to initiate her labor, though Sheldon wants to play a complicated board game instead. Amy shocks Howard by saying Bernadette has already decided to name the baby after her father, Michael. He doesn't agree and everyone makes suggestions as to what to name the baby. Bernadette goes into labor and gives birth to a son named Neil, after Neil Armstrong, Neil Gaiman, and Neil Diamond, with Michael as the middle name. At the last minute, Howard relents to name him Michael as Bernadette got six stitches.
Sheldon needs half a billion dollars to prove his latest concept of string theory, which the University cannot afford to fund. Crowdfunding and selling some of his most valuable comic books to Stuart give him a small start. When Raj mentions gambling in Las Vegas, Sheldon goes there but is caught calculating odds by security before he can make any bets. Meanwhile, Amy takes Penny and Bernadette shopping for her wedding dress. She loves an old-fashioned one that the other girls admit that they find ugly, though Penny assures Amy she can make her own decisions about her wedding. Sheldon, however, comes home and sees Amy in the dress and loves how she looks.