Big Bang Theory star Jim Parsons led one of the highest grossing TV shows of all time, but his success came with a steep price he revealed.

The four-time Emmy-winning actor, 53, said he was “miserable” at the height of his career, because of the pressure and discipline he placed on himself to succeed.

Sheldon and Amy Jim Parsons and Mayim Bialik

Jim Parsons played Sheldon Cooper for 12 seasons of The Big Bang Theory, pictured with co-star Mayim Bialik. CBS

“I look back now and realise that there were many ways, at some of the best moments of my life, I was miserable,” Parsons said during an appearance on All Out with Jon Dean this week. “I was not happy. I was stressed”.

The actor felt he was juggling so many plates because he felt “the success and good things of life” were only happening “due to this overworking” or the “discipline” he instilled.

“Maybe to a degree that was true. I don’t know,” he admitted on the show. “But I wouldn’t do that again and for any amount of money … just because it was stressful and miserable at times. I made myself miserable.”

“Because of your own work ethic?” host Jon Dean clarified.

Parsons explained it was in part work ethic, “but it was really just obsessive behaviour basically”.

The actor revealed he would always have a “list of things” in his head he had to get done to feel comfortable and to know that he could do his job right, which looking back, he now feels wasn’t true.

Parsons said he missed out on “tons of life” because of the obsessive routine he had built for himself.

Parsons opened up about the “stress” he created for himself on All Out with Jon Dean.  YouTube/@jondeanallout

But, he acknowledged that his perfectionism did help get him to where he is today.

“I wouldn’t be where I am right now if I hadn’t had that time of life,” he reflected.

Parsons played Dr Sheldon Copper in the hit sitcom from 2007 to 2019. The series ended after a mammoth 12-season run.

Simon Helberg, Melissa Rauch, Kaley Cuoco, Kunal Nayyar, Jim Parsons and Johnny Galecki.

Parsons with the cast of The Big Bang Theory, one of the most successful TV shows of all time.  Instagram

Jim Parsons

Parsons would go on to win four Primetime Emmy Awards for his role as Dr. Sheldon Cooper.  Getty

Parson’s paycheck of $US1 million ($1.5 million) per episode made him reportedly the highest-paid actor in television at the time according to Celebrity Net Worth.

The Big Bang Theory launched his career in Hollywood, leading to roles in Hidden Figures, Extremely Wicked, Shockingly Evil and Vile and The Boys in the Band, as well as becoming the executive producer and series’ narrator for Young Sheldon.

The spin-off and prequel ran for seven seasons from 2017 to 2024. Parsons narrated all 141 episodes of Young Sheldon.