The 20-year-old took 20 County Championship wickets last term and has been rewarded with fresh terms
Henry Crocombe has agreed to a new contract at Sussex until 2024.
The 20-year-old impressed in taking 20 County Championship wickets last season.
Crocombe also claimed three scalps in the One-Day Cup.
He follows Jamie Atkins, another young quick-bowler, in committing his immediate future to the Hove club.
Previously on rookie terms, Crocombe emerged during the Bob Willis Trophy in 2020 and hopes to build on an encouraging start to his professional career.
“When this new contract was offered to me, not only was I really pleased and excited, I was also really pleased that Sussex have shown their faith, belief and confidence in me to be able to continue and improve my all-round game," he said.
“It’s a really exciting time to be here at Sussex alongside players I have grown up with and played many times with over the years.”
Crocombe is among an exciting batch of youngsters at Sussex
Championship and one-day head coach Ian Salisbury: "It’s great news to secure the services of another of our highly talented, homegrown players for the foreseeable future.
"It gives us the opportunity to work closely with Henry to help him develop both on and off the pitch, where he has the potential to achieve great things with Sussex and beyond.
"Henry has already come on leaps and bounds over the last two seasons. He showed great resilience last summer as our one bowler that was fit for every single game and his performance prompted nearly every opposition coach to comment that he had something special. We’re looking forward to nurturing his talent in the years to come."
T20 head coach James Kirtley added: “His bowling goes from strength-to-strength and it was great to see him finishing the season strong. It is indeed strength that will take him to the next level as it will help him deliver even more effective spells more often and more regularly through a game and a season."