most iconic role is, without a doubt, Sheldon Cooper on which ran from 2007 to 2019. For 12 seasons, Parsons portrayed Sheldon Cooper, a theoretical physicist researching quantum mechanics and string theory, who excels at his work but lacks social skills. Still, Sheldon manages to main good friendships, especially with his roommate and fellow physicist Leonard Hofstadter (Johnny Galecki), as well as their across-the-hall neighbor Penny (Kaley Cuoco). Later on in the show, Sheldon even begins a romantic relationship with neurobiologist (Mayim Bialik), who is matched with Sheldon on a dating app based on their high level of compatibility. By the end of the series, the two have married and even won a Nobel prize for the scientific research they collaborated on.

But "The Big Bang Theory" was not Parsons' first time on a television comedy. Long before he portrayed Sheldon's arc on the hit show, the actor got his start on a long-forgotten sitcom from the 2000s — and acted opposite another major sitcom actor. 

Parsons had a guest role on Ed alongside Julie Bowen

Jim Parsons' first-ever on-screen role was in the comedy series, "Ed," which ran on NBC from 2000 to 2004. The series follows Ed Stevens (Tom Cavanagh), a New York lawyer who moves back to his hometown after getting fired and finding out that his wife is having an affair. Julie Bowen, of future "Modern Family" fame, co-stars as Ed's love interest, a teacher named Carol Phyllis Vessey, who, at one point, almost gets married to her school's principal, Dennis Martino (John Slattery). Parsons played a park ranger named Chet in the third season, which aired in 2002.

Parsons discussed his short stint on "Ed" during an interview with , in which he broke down the highlights of his career. Describing the small part, Parsons said, "The characters played by Julie Bowen and John Slattery were looking for a place to get married and I was there to show them and discourage them — not on purpose though! It's something I bring to the party as an actor as the person who unknowingly gives you bad information."

The actor also discussed how excited he was to be on set and to be able to watch himself on TV when the episode aired. He also noted that working with Bowen and Slattery was a major highlight. Parsons said, "Especially having been on ['The Big Bang Theory'] for so long now, I realize how kind and inclusive they were to me when I was on the set that day." In fact, Bowen even invited him to her trailer, which he admitted he doesn't think he would do for an actor playing such a minor role. "But she did! She was so nice," he continued.

Parsons was nervous after his TBBT audition because of how long it took to hear back

In the same interview with Vanity Fair, Parsons discussed what it was like to land his own leading role in a sitcom, years after his minor role on "Ed." Parsons began by explaining that he knew the part would be a special one, so he spent extra time preparing for his audition (and even skipped an Oscars party). Then, Parsons auditioned and, further, was brought back in for a screen test, which he felt had gone really well. However, despite feeling good about how the test had gone, Parsons began to get a bit nervous because of how long it took for them to get back to him.

Parsons explained, "Normally, any other pilots I'd been cast in, my phone had rang literally while I was walking to the car from the audition ... [but] this was hours, it was "

But, of course, Parsons eventually got the good news — but not before some ribbing from his agent. The actor continued, "My agent at the time, I remember calling, and he said, 'What happened today?' and I said, 'Oh god, what do you mean?' and he goes, 'I'm just kidding, you got it!'"