Balsamo beat Lotte Kopecky (SD Worx) and Marta Bastianelli (UAE Team ADQ) to the finish after 17 laps of the final stage's 5.8 kilometre circuit around Madrid.
Van Vleuten crossed safely within the bunch to win the race by 1 minute and 44 seconds ahead of Elisa Longo Borghini (Trek-Segafredo) and 2 minutes and 11 seconds ahead of Demi Vollering (SD Worx).
Stage 4 winner Silvia Persico (Valcar) took out the points classification while Lucinda Brand (Trek-Segafredo) was crowned Queen of the Mountains.
The win caps another brilliant year for van Vleuten, taking all three major titles home to the Netherlands after winning the Giro Donne and inaugural Tour de France Femmes.
Attacks began right from the start of the final stage, with Sara Poidevin (EF Educaction-TIBCO-SVB) going solo after the first lap with a lead of 11 seconds before she was joined by Sandra Alonso (Ceratizit-WNT), Nina Buijsman (Human Powered Health) and Carlijn Achtereekte (Jumbo Visma) to form the day's breakaway.
Crashes in the peloton meant the chase was slow at points and the group were able to maintain a gap until the final three laps when the four riders began to attack each other with their advantage at only 15 seconds.
In the end, Buijsman and Alonso were the last to be caught with 10 kilometres to go as counter-attacks were launched but quickly brought back with a bunch finish looking assured.
Trek-Segafredo, Movistar and SD Worx had prominence as the race entered the final kilometre. Balsamo launched early but found herself in Kopecky's wheel, using her rival's slip stream to go through with daylight and win the stage.
