Morgan told in Mail On Sunday column how he decided to leave the awards early as the Duke of Sussex started to make a speech via video-link from California, but was busy reading news headlines on his phone when he walked into a window.
Watch: Ofcom clears Morgan over Meghan outburst
The 56-year-old TV presenter said: "As I left, I could hear Harry lecturing the audience about the danger of ‘misinformation’ and ‘peddling lies’, without a shred of self-awareness. I chuckled and pulled out my phone to check the first-edition headlines of the newspapers. To my delight, most of them had splashed my victory all over their front pages.
"I felt a sudden rush of exhilaration at the end of what had been a tumultuous but ultimately very satisfying day.
"Then, as I reached the exit, still staring proudly at my phone, I walked straight into a large plate-glass window, banging my head so hard and loudly against it that concerned security guards rushed over to check I was OK.
"I reeled back in agony, semi-concussed and with a cut opening above my right eye, only to see Harry’s massive head filling a nearby screen.
"He was smirking right at me."
The broadcasting regulator last week ruled that Morgan was "entitled to say he disbelieved" the royal couple and that "the restriction of such views would be an unwarranted and chilling restriction of freedom of expression".
Ofcom received 57,793 complaints about Morgan's remarks – the highest in the broadcasting regulator's history.
A spokesperson for the Duke and Duchess of Sussex confirmed that they were among those to lodge a formal complaint.
In the Oprah interview, Meghan said she had approached people in the royal “institution” for help after she had suicidal thoughts, but was turned down.
Morgan said while discussing the interview on GMB: “Who did you go to? What did they say to you? I’m sorry, I don’t believe a word she said, Meghan Markle. I wouldn’t believe it if she read me a weather report."
Later that day ITV released a statement announcing Morgan had "stepped down" from his role as co-host of the breakfast show.
Watch: Piers Morgan spotted with ITV execs following Ofcom ruling