• Scott Boras represented Juan Soto in his negotiations with the New York Mets.
• Soto's deal is the largest contract in sports history.
• Boras said Soto's performance at Citi Field also factored into his decision.

Major League Baseball super agent Scott Boras just negotiated the biggest contract of his life.

On Thursday, the New York Mets signed four-time All-Star Juan Soto to a record-breaking $765 million, 15-year contract. It is the largest deal in professional sports history.

Soto will be the first player in the MLB to earn more than $50 million in a single season.

"Half the league wanted to participate in this," Boras told CNBC's "Power Lunch." "So many teams were seeking this rare value because in the end, it was just good business to acquire it."

Boras talked about the difficult decision Soto and his team had in finding the best fit. One factor in his decision was his recent performance at Citi Field, where the Mets play.

"Juan Soto's performance levels in Citi Field are well known to him," Boras said. "He plays at his highest level of performance and players think about execution. You think about all these factors."

In Soto's 35 games at Citi Field, the left-handed hitter scored 12 home runs, 26 RBIs and had an on-base percentage of .466 and .709 slugging.

His longest home run of his career, 466 feet, came at Citi Field on Aug. 12, 2020.

Boras also shared that it was not all about the money for the 26-year-old player.

"When you're an athlete, you think about all things, but you primarily also think about your routine, your performance," Boras said. "There's vastly more things than the economics."

Speaking at his introductory press conference, Soto said the Mets had treated him like family.

"They showed me a lot of love on the standpoint of what they have and how they're going to try to make it comfortable. That's one of the things that impressed me more, and how they're going to treat everybody around me and my family," Soto said.