Miami Heat coach Erik Spoelstra has agreed to an eight-year contract extension worth more than $120 million, the most committed money in North American coaching history, sources told ESPN on Tuesday night.

Spoelstra, 53, has established himself as one of the most respected and successful coaches in professional sports and the new deal reflects both his and the organization's desire to keep him with the only franchise he's ever worked for in the NBA.

Spoelstra -- who has won two championships and reached the NBA Finals six times -- is the NBA's second-highest-paid coach on an annual basis, behind Gregg Popovich at $19 million per season, but the length of Spoelstra's deal separates him financially from his peers, sources said.

Miami is tied for fifth place in the Eastern Conference with a 21-15 record despite a revolving door of injuries to key players all season.

Spoelstra has been Miami's coach since 2008, when he was appointed to replace Hall of Famer Pat Riley. Since then, Spoelstra has become one of 14 coaches in NBA history to win two titles. As an eighth seed last season, the Heat made a remarkable run through the Eastern Conference playoffs to eventually lose to the Denver Nuggets in the NBA Finals.

He trails only Popovich in terms of tenure with a single franchise and is third behind Popovich and Indiana Pacers coach Rick Carlisle among active coaches in games won (704).

Those 704 victories rank Spoelstra 20th in NBA history. He's fifth all time with 109 playoff victories, trailing only Popovich among active coaches.

Spoelstra began with the Heat in 1995 as a video coordinator under Riley. Over the next 13 years, Spoelstra rose through the ranks to become Riley's assistant and then took over the team once Riley stepped down in 2008.

Two years later, LeBron James and Chris Bosh joined Dwyane Wade in Miami, ushering in a run of four consecutive Finals appearances -- including back-to-back championships in 2012 and '13.

After James left in 2014, Spoelstra and the Heat returned to the late stages of the playoffs with Jimmy Butler in the NBA's Orlando, Florida, bubble in 2020, beating the Milwaukee Bucks and Boston Celtics on the way to losing in six games in the NBA Finals to James and the Los Angeles Lakers.

The Heat then lost in seven games in the Eastern Conference finals to the Celtics in 2022, before reaching the NBA Finals last season after beating the Bucks, New York Knicks and Celtics.

ESPN's Tim Bontemps contributed to this report.