(CNN) -- Jason Priestley played Brandon Walsh on "Beverly Hills 90210" from 1990 to 1998. Having long since hung up his Peach Pit uniform and Beverly Hills Beach Club cabana boy polo shirt, his character became a journalist and departed to take a job at the Washington Bureau of the New York Chronicle, and Priestley left the show four episodes into the series' ninth season.
"I felt that the character of Brandon had kind of run his course. I had explored everything I wanted to explore with him," Priestley told CNN while promoting his new book, "Jason Priestley: A Memoir" (HarperOne) at the New York Bureau of CNN.
"In retrospect, I do regret leaving. Understanding what I do now about story and character, I believe that [Aaron Spelling] was pushing the story in a direction that would have had Brandon and Kelly end up together at the end of the show and I think I probably should have stuck around to its fruition."
Fans of "90210" surely remember Kelly Taylor's (Jennie Garth) "I choose me" speech following Brandon and Dylan McKay's (Luke Perry) showdown for her affections. Brandon wanted Kelly to marry him. Dylan wanted to take her on a trip around the world. But Priestley believes Executive Producer Aaron Spelling had always envisioned Brandon and Kelly riding off into the sunset.
"I think my departure also hurt Aaron's feelings," continued Priestley. "Aaron and I had worked very closely together for a number of years. He gave me a lot of opportunities, and I feel like my departure hurt his feelings and I never meant to do that."
Among the opportunities Spelling afforded the Vancouver-born Priestley was the opportunity to direct several "90210" episodes -- 15 in total. In fact, Priestley directed two of the series' most iconic: The one where Dylan's wife, Toni Marchette (Rebecca Gayheart) was killed in a mob hit mix-up in which Dylan was the target; and the episode where Donna Martin (Tori Spelling) lost her virginity.
"Everyone remembers the candles," Priestly, 44, said of the episode in which Donna had sex for the first time. "But I could only have, like, six candles because they didn't want to pay for a fire marshal, which would have cost $350."
Yep. $350. So six candles it was.
"So I had that one candelabra," recalled Priestley, "and I kept moving it around for every shot and through the magic of Hollywood it looked like a lot of candles!"
As the director, as well as Spelling's friend, Priestley was under the added stress of directing a scene in which the TV legend's daughter loses her virginity -- albeit her alter ego.
"I was in a difficult spot," he said. "I wanted to be respectful, but it had to be sexy. I was kind of walking on eggshells that day."
Priestley also contributed to the dialogue of the show. True "90210" devotees should recall that Brandon had quite a few catchphrases, and Priestley was kind enough to reflect on such Brandon Walsh-isms as:
"Stop the bombing!"
"Seldom right and wrong again."
"Right church, wrong pew."
"Dim sum and den some."
"It's funny that you bring all those sayings up," said Priestley. "Part of the fun of working on 'Beverly Hills, 90210,' for me, was that I got a lot of freedom from our executive producer, Chuck Rosen, to add things, change things. I got a lot of freedom to be creative. My theater training was all improv, that's sort of the world I came from, so the Brandon Walsh-isms you speak of, a lot of them came from me! I've been saying, 'Stop the bombing!' for a long time."
Another reason Priestley regrets leaving "90210" is because the series needed Brandon's Eagle Scout ways to offset the onscreen chaos.
"I think there was no more moral center to the show," Priestley said of Brandon's departure. "There was no more lynchpin. There were no more Walshes in the Walsh House. It kind of didn't make sense anymore. So, I regret leaving the show for all those reasons."
Though it premiered nearly a quarter-century ago, "90210" continues to resonate with audiences.
"It's certainly not the fashions," said Priestley. "I think there were a lot of universal life lessons and truths in that show, and I think that's maybe why it's stood the test of time."
The book goes into all manner of "90210" tell-all, such as Shannen Doherty's shenanigans and what led to her firing. Brenda's bon voyage had nothing do do with Doherty's hard-partying ways and nightclub fights. Spelling actually thought that any publicity was good publicity. Rather, it was her chronic tardiness that held up production, costing Fox a ton of money.
Spelling gave Doherty many chances, but in the end, it was a business decision.
Priestley also writes about who he keeps in touch with (pretty much everybody, but he and Luke Perry are particularly close), his five-year romance with actress Christine Elise (who played the unstable but later redeemed, esteemed Cousteau Institute scholar Emily Valentine), and his not so warm and fuzzy feelings about Tori Spelling's husband, fellow Canadian Dean McDermott.
Priestley is at peace with being forever associated with Brandon Walsh.
"I'm OK with it," he told CNN. "It's baggage I carry with me. But I find as my career goes on, and I have more and more successes in other arenas and with other characters, I find that Brandon becomes less and less part of my life. I find that a lot of people associate me with 'Call Me Fitz' these days."
"Call Me Fitz" is an award-winning HBO Canada half-hour comedy -- available to Americans on DirecTV -- in which Priestley plays an immoral, Sinatra-idolizing used car salesman.
"Jason Priestley: A Memoir" also recalls the prefame days of having Brad Pitt for a roommate, Priestley's later battles with alcohol (he once spent five days in jail on a DUI), and the 2002 race car crash that nearly cost him his life.
Additionally on the professional horizon, Priestley's feature directorial debut, "Cas & Dylan," a road trip comedy starring Richard Dreyfuss, will hit theaters later this year.
Priestley is married to makeup artist Naomi Lowde. The couple has a young daughter and a young son.
"My kids are my greatest achievement," Priestley told CNN. "I love being a husband and a father. That aspect of my life has been a joy."