The win came at a cost though with Rondo suffering a broken hand which Walton has confirmed will rule him out for a few weeks.
James finished the game with a near triple double - 44 points, 10 rebounds and nine assists - to help Los Angeles' 126-117 win at Staples Center.
Rondo is the primary backup to Lonzo Ball and the only other true point guard on the roster, leaving the Lakers looking to a team effort to fill Rondo's void.
"Just trying to learn to control the game better", Ball said of what he has tried to pick up from Rondo, along with being more vocal. Orlando went on a 21-0 run in the fourth quarter which, according to ESPN, is the second largest unanswered run by a team this season.
"He hit his hand on the floor when he went to steal that ball", Walton said.
The Lakers (7-6) have won three in a row to get them over.500 for the first time this season.
He notched his 39th point with an and-one midway through the 4th quarter that gave Los Angeles a commanding 121-106 lead over Portland.
"I'm just happy we got another win". Next man up. Next man up. "Obviously we can't replace what Rondo does for our team and how important he is to our team, but we're not going to make excuses".
James finished the game with 44 points - the first Lakers player to surpass the 40-point mark since D'Angelo Russell in 2017 - and almost had a triple-double on the night with nine assists and 10 rebounds. Lakers coach Luke Walton confirmed the injury to reporters after the game. Knows where everybody is supposed to be.
It was only a matter of time before his career path led him back home. So it's going to be tough having him out.
"He's done an incredible job of kind of getting that second group playing at a really nice rhythm for us", Walton said of Rondo.
"That is where he will be missed the most".