Speaking to the Bay Area News Group on Monday, Kerr called Durant's two-year, $53 million deal a "remarkable gesture."
"I told him it reminded me a little bit of Tim Duncan and his time with the Spurs," Kerr said. "He made max money, and then at key times in his career, he took a little less so they could add a player here and there."
Duncan, who retired after the 2015-16 season, took some reduced salaries throughout his 19-year NBA career but still made more than $238 million with the Spurs, according to Spotrac, a website that tracks contracts. He will be paid $1.9 million over the next two seasons, as the final year of his last contract -- a Spurs-friendly two-year, $10.4 million deal -- was prorated using the stretch provision.
Durant, 28, could have earned as much as $36 million per season had he signed a max deal this season. As it is, the four-time NBA scoring champion will earn even less next year than he did this year.
"The way the league works, the way the CBA [collective bargaining agreement] works, it really kind of is up to the star player at key times to take a little haircut here and there," Kerr told the Bay Area News Group. "Whether that's fair or not, I don't know. But I do know that Tim knew it was dramatically helping his own career and KD understands the same thing.
"In the end, he's going to make a fortune in his career. Already has, and he hopefully is going to win more titles, and that's what he cares about."
The Warriors coach missed six weeks during the NBA playoffs because of painful migraines and nausea that were complications of back surgery he underwent nearly two years ago. Kerr told the Bay Area News Group that he is feeling good after a vacation in Hawaii.
Information from ESPN's Chris Haynes and The Associated Press was used in this report.