Tight end George Kittle and the 49ers took a major step toward their union extending through his entire NFL career.

Kittle signed a four-year extension that keeps him under contract with the 49ers through the 2029 NFL season, he disclosed on Tuesday morning.

Kittle’s new contract is worth $76.4 million over four years with $40 million in total guarantees ($35 million at signing), as first reported on “Bussin’ with the Boys.”

The annual average of $19.1 million in new money again makes Kittle the highest-paid tight end in the NFL. The deal surpasses Arizona’s Trey McBride, whose recently signed contract averages $19 million annually.

“In 2017, our first year with the 49ers, we selected a skinny tight end from Iowa whom we were really excited about. We had high hopes, but no one knew that he would become the player that he is today,” 49ers general manager John Lynch said in a statement released Tuesday morning.

“George’s leadership, enthusiasm for the game, for his teammates, and the Faithful are truly unique and special. He is an outstanding representation for the 49ers on the field and is an outstanding representative for the organization off the field with his investment in the local and military communities. He has a great sense of pride in his role and has put in the work to be one of the best tight ends in the NFL.”

Kittle’s previous deal, which he signed in 2020, averaged $15 million per season.

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So Kittle, one of the most popular players in franchise history, isn’t going anywhere anytime soon.

The finalization of the contract accomplishes one of the top offseason goals 49ers management set.

“We want George to retire a Niner,” Lynch said in February. “He’s a Niner through and through.”

The next major goal for the 49ers’ offseason is the signing of quarterback Brock Purdy to a multi-year extension.

But Kittle’s contract is one of the few bright spots for the 49ers after the early stages of free agency saw a mass exodus of players.

The 49ers cut future salary-cap costs in anticipation of signing Kittle and Purdy to lucrative contracts.

Kittle, 31, was a fifth-round pick by the 49ers in 2017 and the sixth drafted player of the John Lynch-Kyle Shanahan regime.

Through eight NFL seasons, Kittle has 538 receptions for 7,380 yards and 45 touchdowns. He has also distinguished himself as one of the NFL’s best-blocking tight ends.

He has more receiving yards than any tight end in 49ers history. He also holds the three highest single-game totals in 49ers history for a tight end.

And Kittle shows no sign of slowing down, as he led all NFL tight ends with a 14.2-yard average per reception last season while registering his fourth career 1,000-yard campaign.

Kittle caught 78 of the 94 passes of which he was the target. He accounted for 1,106 yards and eight touchdowns.

Kittle is a six-time Pro Bowl performer and a two-time All-Pro. He appears to be on a path that could someday place him in the Pro Football Hall of Fame.

But Kittle was seen as anything but a sure thing when he entered the NFL. He was the ninth tight end drafted in 2018.

As a rookie, he caught 43 passes for 515 yards with the 49ers after accumulating 48 catches for 737 yards in 40 games over four seasons at Iowa.

In 2018, Kittle established the then-NFL record for receiving yards for a tight end in a single season with 88 receptions for 1,377 yards. Kansas City’s Travis Kelce broke the record in 2020 with 1,416 yards.

Now Kittle is under contract with the 49ers through his age-36 season.

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