GLADSTONE, N.J. — Mitt Romney and his wife, Ann, who plan to attend the opening of the Olympic Games in London this summer, now have a personal rooting interest in the event.

Jan Ebeling, Mrs. Romney’s longtime riding tutor, and his horse Rafalca, co-owned by Mrs. Romney, earned a berth on the United States Olympic dressage team on Saturday.

Mr. Ebeling, 53, who has spent a decade knocking on the door of top international competition, made his first Olympic team with a third-place finish here at the United States Equestrian Team Foundation headquarters, a century-old stable built by the financier James Cox Brady to adjoin his 64-room mansion.

While Mr. Romney was barnstorming on a bus tour of swing states, Mrs. Romney watched from a V.I.P. tent as Mr. Ebeling executed a smooth “test” of flying changes, in which Rafalca seemed to skip down the arena, and piaffes, an in-place trot.