A superb cross from Ben Chilwell was finished off by Gray, who celebrated by lifting his shirt to reveal a message that read "For Vichai".
"There are a lot of exhausted people in there now but I am proud of this team and the club, the way everyone has handled themselves has been unbelievable. It is a good balance between emotion and concentration which is hard, now is just the first step and I hope we can continue next week with the same feeling", he said.
Long after the final whistle, as the rest of the Cardiff City Stadium stood empty and still, a vibrant, defiant, boisterous chant rang out from the still packed visitors' section.
Members of the Leicester team including coach Claude Puel are due to fly to Thailand to pay their respects after an afternoon away match against Cardiff City Saturday.
"We're thinking about his family, we're all hurting, but I can't imagine what they're going through".
The visitors felt they should have had a penalty when Sol Bamba blatantly handballed in the box shortly before half-time, but they finally opened the scoring through Demarai Gray's half-volley with 55 minutes on the clock after Ben Chilwell had found him in the box.
"We all spoke about. wanting to play, it's what Vichai would've wanted and that's what we are going to do", striker Jamie Vardy told Sky Sports, adding that they would "honour his name" with their performance.
"Not many, if any moments in my career like that", he said.
James Milner scored his 50th league goal as Liverpool drew at Arsenal 1-1 to move one point clear of second-placed Manchester City.
A richly-entertaining game threw up chances for both sides as Liverpool manager Jurgen Klopp maintained his record of never losing to the Gunners in six encounters.
Callum Wilson had given Eddie Howe's side a deserved lead but rejuvenated Anthony Martial's fifth goal in as many games somewhat fortuitously pulled his side level before the break.
All this weekend's Premier League games will be preceded by a minute's silence, or applause, and players will wear black armbands.
"We were defensively bad".
Tottenham returned to winning ways at Wolves, but were given a scare late on at Molineux in a 3-2 victory.
Newcastle earned their first league win this season with a 1-0 success against Watford at St James' Park.
West Ham host Burnley at the London Stadium looking for a first win since September.