The margin of victory over silver medalist Meg Harris, Australia, was 26 hundredths. Zhang Yufei, China, took bronze. Sjöström was a strong favorite ahead of Sunday's final and many believed she would break her own world record (23.61) after setting an Olympic record (23.66) in Saturday's semifinal.
The clock stopped at 23.71.
A mistake in the ascent after the start meant she couldn't challenge her own world record.
My first stroke was really bad. But I knew beforehand that even if I make some mistakes, I have a really high level. I went in with confidence and believed I could do under 24 seconds, she says.
"This is my peak"
This is the 38th time she has done a time under 24 seconds – something that has made Sjöström completely superior on the distance where she has won four World Championship golds, three in a row.
Now she has also achieved full success in the Olympic Games.
Sjöström has previously talked about competing in a sixth Olympic Games in Los Angeles 2028.
You never know what happens, but I'll never be better than now. This is my peak. I'm so proud, she says and continues:
I'll keep swimming for several years, but I'll never beat this, she says about the full success with two golds in Paris.
Medal from Lindberg
Sarah Sjöström stepped up to the podium and received the gold medal from Swedish IOC member Gunilla Lindberg.
Sjöström now has a total of six Olympic medals, including three golds, and Sweden's greatest swimmer of all time is also the best "blue and yellow" Olympic swimmer in history.
The duo Gunnar Larsson and Håkan Malmrot have two Olympic golds each.
With this year's two golds, Sarah Sjöström also takes the step up to shared first place among Swedish female athletes with the most Olympic golds. She now shares first place with canoeist Agneta Andersson and cross-country skier Charlotte Kalla.
Sjöström's world record on 50 freestyle was set at the World Championship in Fukuoka, Japan, last summer.
Sarah Sjöström 3 gold – 2 silver – 1 bronze.
Gold: 100 meter butterfly 2016, 50 and 100 meter freestyle 2024, silver: 50 meter freestyle 2021, 200 meter freestyle 2016, bronze: 100 meter freestyle 2016.
Gunnar Larsson 2–0–0.
200 and 400 meter medley 1972.
Håkan Malmrot 2–0–0.
200 and 400 meter breaststroke 1920.
Arne Borg 1–2–1.
Gold: 1500 meter freestyle 1928, silver: 400 meter freestyle 1924, 1500 meter freestyle 1924, bronze: 400 meter freestyle 1928.