Howard Was Written Specifically for the TBBT Star… but Not for Simon Helberg
Thank God, things worked out differently.
One of the biggest strengths The Big Bang Theory has always had over many other shows is its cast. With such special and prominent characters, it's almost impossible to imagine anyone but the actors who were ultimately cast to fill the shoes of Sheldon, Leonard, Howard, Raj, and Penny.
But finding the talent to fill those roles was no easy task. Once everything seemed clear after all the changes made to Penny, series co-creators Chuck Lorre and Bill Prady were able to catch their breath, but not for long.
The role of Howard Wolowitz, which had been written specifically for Kevin Sussman, became available when the actor couldn't fit it into his schedule.
It was actually the actor's role in ABC's Ugly Betty that kept him from fully devoting his time to the new show. That was even more unfair, knowing that his arc on the other show had been as good as complete by that time.
Many years later, Bill Prady recalled this unfortunate coincidence in Jessica Radloff's book, The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series:
“The part of Wolowitz was written for Kevin. We loved him, especially after he first came in and auditioned for Leonard in the first pilot. [ABC] wouldn’t let Kevin out of his contract, even though his arc on Ugly Betty was done at the time,” he reflected on the events.
As unfortunate as it was at the time, it all worked out in the end. Although Kevin Sussman didn't get as big of a role on the show as he was supposed to, he still ended up being a series regular as Stuart. Also, his departure gave Simon Helberg an opportunity to take over the role and bring Howard to life in his own unique way.
Also, with the new The Big Bang Theory spin-off confirmed by HBO, there is still a chance for fans to see more of Kevin Sussman's Stuart in the future.
If you want to watch The Big Bang Theory from the beginning and see how perfect the show is with the cast that we got, you can stream it on Netflix or Max.
Source: The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series