Daniel Sturridge's goal on the stroke of half-time was enough to give Britain, back in the tournament for the first time since 1960, top spot in Group A and a last eight meeting with South Korea back at Cardiff's Millennium Stadium on Saturday.
He slid the ball home from close range after good approach work from Joe Allen and, although they came close to scoring several times, Uruguay, who last competed in the Olympics when they won their second gold in 1928, could find no response.
"Today has been a fantastic day for Britain at the Olympics winning our first golds and we are happy to play our small part in that success this evening and delighted to get to the next stage," Britain coach Stuart Pearce told reporters.
Uruguyan coach Oscar Tabarez lamented: "We have a fine history in this competition from before, but it is a hard competition to win. It is so intense. We were not at our best, but Britain defended very well, especially their goalkeeper Jack Butland."
Fears that the national anthem would be booed by the Welsh crowd came to nothing with a stirring rendition but the crowd were hugely disappointed before kick-off when the team was announced and Britain's skipper, Cardiff-born Ryan Giggs was not in it.
Britain, fielding four Welshmen in their starting line-up, settled first, with one of that quartet, Aaron Ramsey showing the way with a superb performance in central midfield that tipped most of the play Britain's way.
