Vokes has made just four league starts since joining Wolves from Bournemouth in May 2008 and has been linked with a temporary move to Elland Road for some time.
Winger Gradel's signing comes as a bit of a surprise but Leeds manager Simon Grayson was delighted with the double swoop.
"We're delighted to bring in both players," he told the club's official website
"Both lads are still young, but they have good quality about them and they add to what we have at the club.
"Sam is a highly-rated goalscorer and Max has plenty of pace, and both players fit in well to the squad we have here.
"I'd like to thank both Wolves and Leicester for allowing them to come here."
Vokes will stay until January while Gradel is only on a month long loan.