Buck has penned a one-year extension, keeping him in Northampton until the end of 2022.
After coming to Wantage Road in 2017, Buck has been a staple of the club’s attack in red and white ball cricket.
And he said: “I’m very pleased to have extended for another year, I’ve enjoyed my cricket a lot since I made the move here and feel like I’ve developed as a player a lot as well.
"I’m keen to keep playing for the Steelbacks and contributing to getting as many wins as I can for the team.
“I think every year you play there’s always that element of pressure there where you always want to do well and want to perform, and naturally going into the last year of a deal there is that added little bit of pressure.
“But for me personally I’m in a very good place with my cricket, after last year’s adapted season I felt like I was bowling really well, probably the best I’ve bowled for many years, so I’m keen to extend and build on what I had last year.
“Coming into this year now after a really good pre-season, I’m probably in one of the best places I’ve been so far.”
Bowling coach Chris Liddle has been impressed by Buck and the qualities he offers as a cricketer.
“Nathan showed us consistently last summer the qualities he has as a bowler and that’s what we want from our senior players," Liddle said.
“His skillset with the ball is second to none and to have a bowler like Nathan who feels comfortable to bowl at any stage of a game and in any format is fantastic.
“He’s a big part of our bowling group and like the other senior bowlers it’s about leading by example and setting high standards.
"We have a great group of bowlers here who keep striving to get better and I’m looking forward to seeing Nathan kick on from last summer.”