The Boston Celtics have prioritized winning championships over everything, and they've put their money where their mouth is to start the offseason. On Monday afternoon, guard Derrick White agreed to a four-year, $125.9 million contract extension with the Green Team. Just a few hours later, star Jayson Tatum finalized a five-year, $315 supermax extension with the Celtics in what's now the largest contract in NBA history.

That's over $440 million dedicated to two of Boston's starters. The rest of the Celtics' top five, including star Jaylen Brown, veteran guard Jrue Holiday, and center Kristaps Porzingis, are also all under contract next season.

These major moves will put the C's over the second tax apron, resulting in plenty of restrictions under the new CBA. However, winning is the best cure for financial woes, and the Celtics did just that in the 2024 NBA Finals after dominating the Dallas Mavericks in five games.

Two weeks after winning banner no. 18, the Celtics announced on Monday that their current ownership group, led by Wyc Grousbeck, was planning to sell its majority interest in 2024 or early 2025 at the latest. Grousbeck, who's won two titles in his 22 years as a Celtics executive, will stay with the franchise until 2028.

While unexpected, this significant change shouldn't shift Boston's ultimate goal of maximizing its championship window. The first steps towards the C's continuing their winning ways started this summer, so let's delve into why Tatum and White deserve their massive paydays.

Why Jayson Tatum is worthy of his record-breaking deal

Boston Celtics guard Derrick White (9) and Boston Celtics forward Jayson Tatum (0) react
Trevor Ruszkowski-USA TODAY Sports

Jayson Tatum's resume speaks for itself. He's a five-time All-Star and three-time All-NBA First Teamer.

Despite those impressive accomplishments, Tatum earned his best honor in June after becoming an NBA champion.

It took seven seasons, but he was rewarded for his patience with one of the best Celtics teams in recent memory. Brown, who previously held the richest contract in league history, won Finals MVP and Porzingis and Holiday were crucial offseason additions.

Tatum was the on-court commander that Boston needed in the postseason, as he led his squad in points, rebounds, and assists. He's only the sixth player ever to lead a team in those categories while winning a championship.

When the Celtics asked him to deliver, he did. In Game 5 of the Finals, he put up one of the best performances of his playoff career, dropping 31 points, eight rebounds and 11 assists en route to a series-clinching victory. The St. Louis native is the only player in franchise history to post over 30 points and 10 assists in a Finals game.

Since Tatum came into the league in 2017, expectations were sky-high. He showed that he could compete at the highest level during his rookie season after dunking on future Hall of Famer LeBron James in Game 7 of the 2018 Eastern Conference Finals.

Following that series defeat, almost every playoff failure the Celtics endured was held against Tatum. Some talking heads wondered if he'd ever win it all alongside Brown, arguing that the dynamic duo was more offensively stagnant than complementary.

The cries for a breakup grew louder, yet Tatum and Boston's front office didn't let the outside noise in. He gave the executives a title and they provided him with the ultimate sign of trust, a supermax extension.

Tatum made good on his promise to raise another banner in the rafters of TD Garden, and he was rewarded fairly for it. Several other stars would've demanded a trade at the first sign of conflict or crumbled under the championship expectations that come with playing in Boston—the 26-year-old withstood the blows and stayed the course.

It's hard to put a price on Tatum's experience, stardom, and maturity, but $315 million sounds like an appropriate figure.

Why Derrick White's contract is another slamdunk for the Celtics

A championship doesn't happen without high-end talent like Tatum and Brown. It also doesn't happen without glue guys like Derrick White.

The two-way guard comes from humble beginnings, starting his collegiate basketball career in Division II. From there, White has developed into a fringe star player who probably exceeds the typical “role player” label.

Although he's never been named to an All-Star team, White got close during the 2023-24 campaign. He averaged 15.2 points while shooting 46.1% from the floor, 39.6% from deep, and a career-high 90.1% from the charity stripe. The Colorado native averaged a career-high 1.2 blocks per game as well, the most of any guard in the entire league outside of Toronto Raptors star Scottie Barnes (who's three inches taller than White).

Not too long after White first arrived in Beantown, he struggled in the 2022 NBA Finals. In the wake of that series disappointment, he's been just about everything Boston could ask for in the clutch.

Take this year, for example. He notched a career-high 38 points in Game 4 of the first round against the Miami Heat and cashed the series-sealing 3-pointer in Game 4 of the Eastern Conference Finals versus Indiana Pacers.

Then in Game 2 of the 2024 NBA Finals, White had another signature playoff moment. He chased down Mavs forward PJ Washington and blocked him at the rim with under a minute to go to maintain Boston's 103-98 lead.

To put it simply, White makes winning plays. Plus, his $125.9 million contract is arguably a steal in some ways. He'll earn around $31.5 million a year, which isn't as much as it used to be in the Association.

Toronto Raptors point guard Immanuel Quickley is actually getting paid more annually thanks to his new five-year, $175 million deal. While there's no denying the 25-year-old's talent and upside, he's less efficient and a worse defender than White. Quickley has the skills to become an All-Star in the future, yet the fact that he's worth more than the third-year Celtic right now exemplifies how great White's extension could be.

With Tatum, White, and the rest of the starting five locked up for next season, the Celtics will hope to see another title stem from all their summer spending.