The 23-year-old secured a comfortable 13-6 win over Junior Castillo Martinez at ExCeL, winning all three rounds against the boxer from the Dominican Republic.
And Ogogo, who will face world champion Evhen Khytrov from Ukraine in the next round, revealed his nerves before dedicating the win to his family amid the imminent arrival of a niece or nephew.
“It’s something I’ve been dreaming of since I was a kid,” said Ogogo. “It was better than I thought it would be.
“I feel so proud and I’m so lucky. My sister was admitted to hospital today because she’s pregnant. She’s gone into labour. I just wanted to give something back to them.
“I was a bit tense after the opening round. I was a bit nervous and it was a bit nerve-racking. Eventually I settled down and got into my rhythm. I let my shots go and I’m glad I got the win.”
Ogogo, who worked hard to recover from shoulder surgery that put his qualification for the Games in doubt, worked his left hook well as Castillo became more desperate to claw back the points.
The British boxer will be buoyed by the nature of his victory, and will be confident against Khytrov in the second round on Thursday.
Another British boxer, Luke Campbell, received a bye into the second round of the men's bantamweight competition, where he will face Jahyn Parrinello after the Italian defeated Namibia's Jonas Matheus 18-7.