Out of nowhere, Brian Murphy’s cellphone started buzzing in February.

General Manager Rick Spielman had just told Vikings beat reporters that he was optimistic about the chances of signing star safety Harrison Smith to a contract extension. That tidbit was tweeted out to the masses, trumpeted into the NFL blogosphere and quickly echoed by about 30 people to Murphy, who is the agent for Smith and a few other prominent Vikings players.

“I’m guessing that was Rick’s way of kick-starting the negotiations,” Murphy, one of the lead agents at Athletes First, said with a chuckle last week, several hours after Smith signed his five-year, $51.25 million extension.

Over the past 3½ months, Murphy and Rob Brzezinski, the team’s vice president of football operations and lead contract negotiator, were in near-constant communication about a potential deal. They lobbed offers and counteroffers before both sides gladly agreed to a deal Monday morning that made Smith the league’s highest-paid safety.

“I do have him on speed-dial,” Murphy said, referring to Brzezinski. “Over the past four, five, six years, we’ve established a really good relationship.”

That doesn’t mean the Vikings threw in a couple of extra million for Smith. But their familiarity with Murphy after he handled negotiations for past deals with clients Everson Griffen, John Sullivan and Kyle Rudolph helped pave the way for them to get Smith under contract sooner than expected.

“I think at this point, we understand we have a common goal and we are kind of partners in working toward that common goal,” said Murphy, who also represents Trae Waynes, the team’s top pick in the 2015 NFL draft.

Smith, for the most part, stayed out of the negotiation process, trusting Murphy to get the deal done. Murphy, a Notre Dame alum, has represented the fellow Golden Domer since Smith left Notre Dame for the NFL in 2012.

“Just a very genuine person,” Smith said of Murphy. “We had that connection outside of business. He’s a bright guy, he’s got a proven track record, does things the right way. There’s a lot of horror stories with fighting and agents and teams, and that’s something I don’t want. I want things to be fair for both sides and I think that’s something he’s always done a good job of.”

Murphy, 45, grew up in the Boston area and after graduating from Notre Dame he returned to attend Harvard Law School. Throughout college he was intrigued by the possibility of a career working with sports figures.

Murphy had been working as a negotiator at a law firm in Boston for about five years when a representative from Harvard called him in 1999 to ask if he still had interest in becoming a sports agent. Superagent Leigh Steinberg had just posted a job listing looking for “the next Jerry Maguire,” the title character from the 1996 movie for which Steinberg was the inspiration.

Murphy called Steinberg’s agency to inquire about a position and after a lengthy interview process got the job. He moved to Southern California to work for Steinberg for two years before joining Athletes First, which during his 15 years there has grown into one of the league’s premier agencies.

Murphy, who now lives in Newport Beach, estimated that Athletes First represents about 125 NFL players. They list 11 certified contract advisers on their roster and have a marketing and public relations team.

“They take care of a lot of stuff for their clients, try to make life easier so you can focus on playing football,” said Sullivan, who hired Murphy in 2008.

Athletes First’s clientele includes All-Pro players such as Green Bay Packers quarterback Aaron Rodgers, Denver Broncos pass rusher Von Miller and Seattle Seahawks safety Earl Thomas, who was the NFL’s highest-paid safety at $10 million per season before Murphy negotiated Smith’s megadeal.

Smith’s deal, which expires in 2021, averages $10.25 million per season.

“I think the reason the deal got done now instead of the summertime is because we were both very forthright with each other,” Murphy said.

“We knew exactly what we wanted. Harrison wasn’t going to do any deal that didn’t make him the highest-paid safety in the league. And we knew they weren’t going to do a crazy free-agent deal because he’s not a free agent.”

The deal done, Murphy has more downtime than he knows what to do with.

When he wasn’t negotiating with NFL teams, Murphy had been coaching his two daughters, Mackenzie and Brittany, on the soccer field. Rudolph and Smith have showed up in the past to cheer them on.

But his daughters are teenagers now. Mackenzie switched her focus to dance and Brittany moved on to play for a club soccer team sponsored by NBA great Kobe Bryant.

And his five Vikings clients might not be up for new contracts for a while, so Murphy doesn’t have a reason to speed-dial Brzezinski and the Vikings.

“I really don’t have anything to do. I’ll have to find a new hobby,” he joked.