The new plans are a significant change to Artemis programme.
Isaacman said the current architecture was "not a pathway to success."
"You don't go from one uncrewed launch of SLS [Artemis I], wait three years, go around the Moon [Artemis II], wait three years and land on it."
He said sending the Orion capsule - which is the spacecraft that the astronauts will travel to the Moon in - and a lunar lander into low-Earth orbit first would reduce risks.
"I would certainly much rather have the astronauts testing out the integrated systems of the lander and Orion in low-Earth orbit than on the Moon," he said.
"It's also an opportunity for us, maybe, to get our suits up there before the astronauts actually have to wear them on the surface of the Moon ... this is all going to help take down risk for a subsequent landing."
However Nasa's lunar plans have a major missing part - the lander that will take astronauts to the Moon's surface has not yet been selected.
Elon Musk's SpaceX company has a contract to build the lander - which will be flown to the Moon on a SpaceX Starship rocket. But delays to the Starship rocket have led Nasa to ask SpaceX for a new streamlined plan to speed a return to the Moon.
Nasa has also asked rival company Blue Origin - which is owned by Jeff Bezos - to come up with an accelerated plan for a lunar lander.
Isaacman said the Artemis III docking in low Earth orbit could take place with one or both of the landers.
The US is under pressure to return to the Moon. China is aiming for a lunar landing by 2030, and has been making steady progress towards this.
Both nations are planning to land at the Moon's south pole - and are competing for the best spots to build their lunar bases.