John Cena described his rough patch, recalling being homeless and surviving on pizza when he first arrived to Los Angeles, California in 1999.
The WWE star turned actor, 46, told comedian Kevin Hart on his show Hart to Heart that after college, 'every avenue of fitness failed' him.
Cena had planned to use his exercise physiology degree but was repeatedly turned down, prompting him to apply to become a highway patrol officer.
'[I] came out here to put my degree to use and completely failed... I couldn't obtain any confirmation for the paper I paid for. "We think you know what you're talking about," he continued, referring to his four-year diploma from Springfield College.
Cena survived by sleeping in the back of his 1991 Lincoln Continental and eating pizza from a neighbourhood eatery that provided a 'eat the whole pie, get it free' bargain.
Cena had wanted to find a position that would allow him to use his degree, but it proved to be more difficult than he could have expected.
'I didn't go out to LA to seek showbiz,' he said to Hart, describing how he hoped to find a fitness-related job.
'I moved out to put my degree in exercise physiology and kinesiology to use,' he explained before Hart chimed in.
'It's really just a degree in working out,' Cena humorously responded.
When Hart questioned the WWE superstar why he didn't find success in Los Angeles, Cena claimed he couldn't say for sure, but it may have been a lack of experience.
'Knowledge is one thing; life experience and wisdom are quite another,' he explained.
Cena continued, saying that the attacks kept coming and that he had 'failed to the point of' living in his car and eating free food from Zeppy's Pizza in Hermosa Beach.
'They had a promotion where you could eat their entire pizza for free,' Cena explained. 'I used to dine there every night, a full pizza, since I didn't have the money to pay the guy.'