The 21-year-old performed with his band, The Breakers, at both Reading and Leeds festivals, capping off a busy summer of touring across the UK.
Cruz, the youngest son of David and Victoria Beckham, drew a packed crowd at Leeds, where he performed in a casual T-shirt and denim jeans.
Cruz Beckham and the Breakers performing on the stage. Photo: Jeff Moore/PA Wire (Image: jeff moore)
He later posted on Instagram to reflect on the milestone, describing the shows as the biggest of his career so far.
He also paid tribute to his girlfriend and manager, Jackie Apostel.
Cruz said: “I am so grateful for everyone around me, not only are they my best friends but they are family, this journey has been so incredible and I have learned so much because of these people.
“To the fans and everyone who came to the gigs, I am forever grateful for every single one of you, you are the reason this is happening.
“You are the reason I wake up in the morning and look forward to hanging out with you and chatting, I love you.”
He also thanked Ms Apostel for her support and guidance.
He said: “Last but definitely not least Jackie, you honestly have no idea how lucky we are to have you, not only do you take care of me but this whole operation, from creative to strategy to mgmt.
Raye was one of the headliners on Sunday. . (Image: Jeff Moore)
“We are a team and would not be doing this without you.
“I really love you so much.”
Ms Apostel replied in the comments: “I love you.”
Family support was also front and centre over the weekend, with David and Victoria Beckham seen cheering on their son during his Reading Festival debut on Saturday.
The couple had reportedly just returned from a holiday on their £16 million yacht in Europe, making it back in time to see Mr Beckham perform on The Canopy stage.
This year’s Leeds festival is expected to draw around 90,000 people, with music continuing across multiple stages until late evening.
Dave and Raye provided the closing performances for this year’s event.