An introduction should not be necessary. Dave O’Brien is one of the more accomplished and prolific broadcasters working today. He has called eight no-hitters and nine World Series. He narrated Barry Bonds’s record-setting 756th home run. In nine seasons in the Red Sox radio booth, he has delivered some big-moment calls that became instantly timeless, none topping his “David Ortiz! David Ortiz! David Ortiz!’’ exclamation after the Red Sox slugger’s series-shifting grand slam in Game 2 of the 2013 American League Championship Series.

“Nothing I’ve done has been quite as special for me as being at the microphone for all of that October, calling a World Series victory for a Boston audience,’’ said O’Brien, 52.

You know his voice. Between his gigs with the Red Sox and ESPN, he broadcasts an estimated 225 games a year. But perhaps a reintroduction is in order, for in the aftermath of NESN’s graceless handling of its decision to dismiss the popular Don Orsillo after 15 years, a truth was lost in the backlash: The decision to have O’Brien shift from the radio booth to replace him was something of a coup, a hiring that almost assuredly will result in a superb broadcast, with Jerry Remy, Dennis Eckersley, and Steve Lyons serving as his cadre of color-analyst collaborators.

Orsillo, who quickly landed with the San Diego Padres, is an outstanding broadcaster, but a portion of his popularity on NESN was based in familiarity. He may never have been in your living room, but his voice and visage were every night, promptly at 7:05 p.m. Fans didn’t know him, but they sure felt like they did — and they felt for him when he lost his job. It seemed unjust.

But it would be nearly as unjust if viewers hold NESN’s decision against O’Brien, a native New Englander and lifelong Red Sox fan. He debuts as the Red Sox’ television voice Monday with NESN’s broadcast of the annual exhibition doubleheader against Boston College and Northeastern.

“This is a dream come true,’’ he said, one that was made possible by a talent and ambition he discovered before he was even out of high school.

Finding his voice

O’Brien was born in Quincy and spent his early childhood in Marshfield. When he was a young teenager, his parents and their four boys moved to Keene, N.H. It was there that he discovered his love of sports — he played third base for Marlborough High’s 1980 state champ­ionship baseball team.

O’Brien also discovered two truer loves there. He met his future wife, Debbie, and he realized a passion for broadcasting, in part through the audio osmosis of listening to Red Sox games with his dad, Robert.

“My dad would listen to the game while he was working in the office every night in the top floor of our house,’’ said O’Brien. “Two bedrooms over, I’d be listening to the broadcast and my dad’s commentary while doing my homework. That planted the seed.’’

When O’Brien began finding his own voice, it was at a place not quite as glamorous as Fenway: It happened at a school radio station that operated out of the vocational wing of Keene High School. Students who were interested were allowed to be on the air. O’Brien was interested enough to bus over from Marlborough High to participate; soon he was hooked.

“I think maybe they could hear it as far down as the gymnasium,’’ O’Brien said with a laugh. “But that moment you turn on the microphone and hear the sound of your voice, it’s like a lightning bolt. I knew in that moment that this is what I wanted to do.’’

That heady experience led O’Brien to introduce himself to Howard Corday, the program director at Keene station WKNE. Impressed, Corday offered the precocious teenager a chance to work nights and weekends at the station while operating the board during Red Sox broadcasts.

“When Dave came to talk to me, I was blown away,’’ said Corday. “He had great pipes, a really good voice. But he had a confidence about him that a lot of high school kids, a lot of adults, don’t even have.’’

Corday soon gave O’Brien more responsibilities and airtime. “I was spinning records, old 45s, top-40 stuff. A lot of Donna Summer on my show,’’ O’Brien said with a chuckle. “Then slow it down with a little John Denver.’’

But he was not destined to be the next Casey Kasem. Corday told O’Brien he had a “sportsy’’ cadence. He had attended Syracuse University, a renowned incubator for sports broadcasting talent. Marty Glickman, Marv Albert, Dick Stockton, Bob Costas, and Sean McDonough are among the more notable alums in the field. Corday recommended that O’Brien should follow his dream to Syracuse. O’Brien didn’t need to hear the suggestion twice.

Tracking career path

When O’Brien arrived for his freshman year at Syracuse, he’d already accumulated more than 100 hours on the air at WKNE. But airtime at Syracuse’s student radio station, WAER, would not be easy to come by.

“We had our whole thing established,’’ said Mike Tirico, the longtime ESPN “Monday Night Football’’ play-by-play voice who was a year ahead of O’Brien at Syracuse and had already joined WAER. “It was incredibly competitive, with very few opportunities to do games. So here comes this guy, joining us, and we’re like, ‘Hey, what’s the deal?’ When you’re 18 and a guy goes for a big play, you’re lucky if your voice doesn’t crack. And then Dave opens his mouth and he’s got the voice of a 40-year-old. And we’re all going, ‘Aw, c’mon, this isn’t fair. This is b.s. We’re older, and he comes in here with the voice of God.’ ’’

O’Brien thrived at Syracuse, calling many memorable basketball games at the Carrier Dome during the pinnacle of the Patrick Ewing/Chris Mullin/Pearl Washington Big East era. His first break came roughly the same time he tossed his mortarboard in the air at graduation when he was offered a job at a small radio station in Spartanburg, S.C. Newly married to Debbie, they packed their Subaru and headed south.

Six months later came a bigger break. WSB in Atlanta, which held Braves broadcast rights, was interested. He interviewed with the program director, Brad Nessler, at halftime of a Falcons game. Nessler offered O’Brien the job before the second half began.

O’Brien began calling Braves games in 1990 on WSB after the retirement of Ernie Johnson Sr., and was one of the voices who called the team’s unexpected run to the 1991 World Series. In ’93, O’Brien became the voice of the expansion Florida Marlins, who were being put together by a young general manager named Dave Dombrowski. O’Brien spent nine seasons calling Marlins games before joining ESPN in 2001.

Even as he found success at ESPN, the career pinnacle for many broadcasters, he continued moonlighting on regional baseball broadcasts, calling 50 or so Mets games per year, mostly on weekends, on WPIX from 2003-05. It was then that the desire to be the voice of a single team again came back to him. He wanted to get back to doing that. He wanted to get back home.

The plan to return to New England was set in motion before he had the Red Sox radio gig lined up. The O’Briens were living in West Palm Beach, Fla., but had begun searching for a home on the New Hampshire seacoast. They quickly found one in bucolic Rye.

“I remember leaving and saying, ‘I love that house, I want to buy that house,’?’’ he said. On the way to the airport to return to West Palm Beach, he turned on WEEI. Nighttime host Mikey Adams was talking about some breaking news: There would be a change in the Red Sox radio booth. Joe Castiglione would be back, but Jerry Trupiano would not.

O’Brien immediately called Mike Dee, then the Red Sox’ chief operating officer, whom he knew through a mutual acquaintance. An interview was set up, and O’Brien joined on for the 2007 season, meshing immediately with Castiglione, the radio voice of the Red Sox since 1983. Castiglione appreciated that O’Brien could be generous in the big moment. Last season, O’Brien, to Castiglione’s surprise and appreciation, turned over the microphone in advance of Ortiz’s 500th home run, even though it wasn’t his inning to call.

“He really knows how to work with partners. He has a knack for bringing out their best,’’ said Castiglione.

That new era unofficially begins Monday. It officially begins Opening Day. O’Brien recognizes that there may still be a segment of Red Sox fans whose disappointment in Orsillo’s ouster carries into the new season, something he may address when he reintroduces himself.

“At some point, probably Opening Day, what I want to say is I hope when you tune in every night to watch the Red Sox, you’ll come to view me as a trusted friend, that I have earned your respect,’’ said O’Brien.

“The same respect fans have given Don, and before Don, gave it to Sean McDonough, and going all the way back to Curt Gowdy, a wonderful line of Red Sox broadcasters.

“I’m going to try very hard to earn that. And beyond that, show up, work hard, and do the job that I’ve been doing for 25 years.’’

Chad Finn can be reached at finn@globe.com. Follow him on Twitter @GlobeChadFinn.