The deal includes $37 million guaranteed.
Lockett was heading into the final year of his previous deal, which was a three-year, $30.75 million extension signed in 2018.
Russell Wilson gave his thoughts on his teammate's new deal:
The extension features an average of $17.3 million per year, which would rank 10th among NFL receivers, per Spotrac.
Heath Cummings of CBS Sports showed why Lockett could be rated even higher based on his numbers:
The 28-year-old set a career high with 100 catches last season while adding 1,054 receiving yards and 10 touchdowns. It's the third straight year he had at least 1,000 yards from scrimmage, scoring 28 total touchdowns in this stretch.
Lockett has transitioned to being a complete receiver from his earlier days as a returner and gadget player. The 2015 third-round pick was named first-team All-Pro as a returner during his rookie season when he totaled 1,915 all-purpose yards with two return scores.
Though he has received limited leaguewide recognition as a receiver, he has formed one of the best tandems in the NFL alongside DK Metcalf and has now been rewarded with a hefty new contract.