In London, when it was announced in 2005 that Valery Gergiev had been appointed principal conductor — and therefore de facto music director — of the London Symphony, I was able to gauge the reactions of a surprised listening public and critical community. They were not entirely favorable. The dean of British critics and author of the definitive volume on the LSO, Richard Morrison, wrote that this was the beginning of the end of that celebrated ensemble’s discipline. Mr. Gergiev almost immediately angered his new constituency by stating that now he could conduct the Saturday matinee at the Barbican and still be home in the evening to lead his beloved Kirov Opera in St. Petersburg.

The jury is still out about the effects of his tenure, but an interesting piece of evidence will air on Wednesday as “Great Performances” presents “Maestro: Portrait of Valery Gergiev” on PBS. It is an entertaining hour, particularly if the viewer does not want to delve too deeply into the issue.

The program relies heavily on footage from rehearsals, and thus we observe three different afternoons in London devoted to Stravinsky’s “The Rite of Spring.” We are exposed to various sides of this complex character. Valery the comedian makes an early appearance as principal bassoonist Rachel Gough stops her opening solo to complain that she cannot follow maestro’s beat. He replies that she should go her own way. He simply feels that it his duty to wave his arms now and then. Privately and candidly, Mr. Gergiev explains that he does not prepare for rehearsals, rather letting his players play and then reacting to what he hears. He describes the rehearsal process as “95 percent unpredictable.”

In a different rehearsal, he is less affable, lecturing his musicians about their lack of commitment. Another session demonstrates that he may still feel like a guest conductor, detached from his new assignment, telling his trombonists that “after tomorrow, you can play it your old way.”

The hero of the piece may be Mr. Gergiev’s manager Doug Sheldon, who runs the energizer bunny’s hectic schedule. We see him on a train, desperately trying to figure out how to get his charge to Madrid for one evening, while Maestro is shoulder to shoulder with him arranging his own affairs. This beast with cell phones in each ear may be the real Valery Gergiev.

Gustav Mahler found the directorship of the Vienna Opera so stressful for both body and mind that he could only compose during his summer vacation. Mr. Gergiev is director of the Kirov Opera at the Mariinsky Theatre in St. Petersburg, and also the director of the Kirov Ballet. In addition to his London post, he is founder and president of the Moscow Easter Festival and principal guest conductor at the Metropolitan Opera, where he is wont to scoot across the plaza after the matinee for an evening of guest conducting at Avery Fisher.

The program shows Mr. Gergiev in several administrative activities, his Mariinsky desk covered with papers as he agrees to attend a lighting rehearsal for the ballet. Later, he must arbitrate a decision as to where to store a piano, and when he meets with a high-level Russian cabinet minister, he empathizes with the man’s crowded airline schedule.

This is PBS, so objectivity is not a major consideration. Titling this piece a portrait is apt; it resembles one of those commissioned paintings that are hung over the fire at a prosperous 18th-century home, depicting the lady of the house in the most favorable light. Based solely on this evidence, all of Mr. Gergiev’s performances are superb. Endorsements from the likes of Renée Fleming, Dmitri Hvorostovsky, Anna Netrebko, and several of the LSO players turn documentary into hagiography.

Those of us who have heard some of his better performances might heartily agree, but those of us who have experienced a night when he seemed off and uninterested — and, ironically, we are the same people — know that Mr. Gergiev can easily be seduced by the passing effect, ignoring the underlying values of the work as a whole. He does seem a strange choice for London, where the orchestra has such a long history of graceful and precise music making. Time will tell.

This fast-paced hour holds the attention of the viewer, but filmmaker Allan Miller never answers the big question about Valery Gergiev. How does he always appear to have not shaved for the past three days?