As part of the Undercover Boss programme, which airs on Tuesday, Birks spent six days working on the shop floor in a variety of stores, posing as a participant in a job placement scheme.
"The best thing was that we got to find out the nitty gritty," he said. "Normally, because of who we are, staff won't talk to us like they would a colleague. We found out things we would never have otherwise."
Birks said he was well aware that his television appearance could have backfired. In a previous episode of Undercover Boss, the MD of takeaway chain Southern Fried Chicken, Andrew Withers, was shocked by standards, staff and customers in his chain, and described his takeaway food as "shit".
"We had reservations when we were approached," he admitted. "But we knew there couldn't be anything really bad exposed. Where we did find issues we have committed to putting them right. There were a couple of people bang out of order, and they get absolutely roasted on camera when we do the big reveal."
Poundworld has opened 28 of its 128 stores this year and one of the issues highlighted was the stores that had been neglected as a result of such an aggressive expansion programme.
"There are some stories of hardship," said Birks. "Had we known about some of the conditions we would have put them right. So there are highs and lows. But as it went on, I felt really proud of the business."
Poundworld managing director Chris Edwards, who couldn't take part because he is too well-known in the business, added: "Appearing on this show has given us a valuable insight into some of the most important parts of the business and we have immediately taken steps to improve the issues it raised."