Bobby Zamora fired the Londoners back into the top flight with a 91st-minute goal in the Championship play-off final against Derby County in May.
With 10 minutes remaining, Redknapp, 67, was standing on the Wembley sidelines wondering what golf club he was going to join.
"If we had not gone up this year I would have stopped," he said.
"I would not have gone back for another year in the Championship. That doesn't appeal to me any more.
"I'm excited to be going to Anfield and Old Trafford but I went to Wembley that day knowing that if we had got beat I'd have turned it in, definitely.
"With 10 minutes to go I was just thinking, 'I don't know what golf club to join next year'."
Redknapp is eager for QPR to avoid making the same mistakes as in 2012-13, when overpaid players saw the club to just four wins and relegation from the top flight.
The former Tottenham and Portsmouth manager said he was looking for players who wanted to represent QPR.
"We are determined not to make those mistakes again," Redknapp said.
"I think [chairman] Tony [Fernandes] and the board have learned from that so we have got to make sure this time, as best we can, we make the right decisions and get the right characters in here.
"We don't want people who are going to come here just for the money and not be interested in the club. We want people who genuinely want to come here and play and do well for us."
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