The Tory minister carried the 17th Century Sword of State and Jewelled Sword of Offering as part of the proceedings for more than an hour and people on social media praised her for her stamina but also made loads of memes about her outfit, even likening the colours she was wearing to the Poundland logo.
Now, reacting to her new meme status, she has told Nick Robinson's Political Thinking podcast she enjoyed becoming a hit on social media.
"I was reunited with my phone and found I had become a meme," she said.
\u201cPenny Mordaunt representing Tory Party Doners at the Coronation. Good skills. Chilli sauce? \ud83d\udc47\ud83d\udc47\ud83d\udc47\ud83d\udc47\ud83d\udc47\ud83d\udc47\ud83d\udc47\ud83d\udc47\ud83d\udc47\ud83d\udc47\ud83d\udc47\ud83d\udc47\ud83d\udc47\u201d
When people compared her to Princess Leia from Star Wars, though, she said "that's not the look I was going for."
Mordaunt, who is the Leader of the House and also Lord President of the Privy Council, carried the 17th century Sword of State made for Charles II into Westminster Abbey, and exchanged it for the Jewelled Sword of Offering, which symbolises royal power and the monarch accepting his duty and knightly virtues.
She carried the Jewelled Sword of Offering, with hilt encrusted with diamonds, rubies and emeralds, for the rest of the service and walked with it in front of the King as he left the abbey.
Quite the feat. She also said she took a couple of painkillers to help her get through the day and made sure she was "in good nick".
"I was not in the gym for six months prior to this" but added: "You want to make sure you are in good nick.
"I did take a couple of painkillers before just to make sure I was going to be alright."
Mordaunt said her navy training in Portsmouth also helped her know how to keep her circulation going by "wriggling your toes".
Anyone hoping to do the same should "practice", "have a good breakfast", and "wear comfortable shoes", she added.
\u201c"You want to make sure you're in good nick"\n\nPenny Mordaunt tells @BBCNickRobinson about her sword carrying exploits at the Coronation\n\n#BBCPoliticalThinking https://t.co/XSWFC39TF6\u201d