Von der Leyen rode into the arena in Aachen among a group of four riders at the head of 68 stallions from Germany's ten state stud farms.
Wearing the uniform of the Celle stud farm in Lower Saxony, she joined in with a quadrille – a display in which four horses or groups of horses perform complex interlocking manoeuvres – in front of the 40,000-capacity stadium.
“The really big stars are the riders and the horses,” the minister told Westdeutsche Rundfunk television before her appearance, promising a “fascinating quadrille”.
“I extended my holidays specially into this time” to spend three days training for the dressage, von der Leyen added.
Von der Leyen is likely to face criticism from some quarters for taking such an obvious break from her duties, as the Bundeswehr (German military) has been crying out for more funding and better administration over the past year.
A series of embarrassing equipment failures in high-profile international interventions has made clear the extent of the damage to Germany's fighting force.
Dressage team defends European title
Now that the festivities are over, the German national dressage team faces a tough battle to defend its title on Wednesday and Thursday.
“We are grimly determined” to see it through, team leader Klaus Roeser said.
Germany must fend off teams from the UK and the Netherlands if they are to make it into a third year as European champions.
The European Equestrian Sports Championships will see 13 titles awarded across five disciplines between Wednesday and August 23rd.
One of the most anticipated events will be the jumps next week.
This year's event is likely to be the biggest ever, with 300,000 spectators expected in the northwestern city of Aachen.