Mr Monks, who succeeded Sir Alan Ayckbourn in 2009, has directed 24 productions, revitalised the literary department and, most recently, conceived and launched a dedicated community facility, the SJT OutReach Rooms.
He will leave the role on December 11. His departure comes in the same year executive director Stephen Wood announced his departure after 25 years with the company.
The duo’s depatures mean the theatre will have a new top team to take them into 2016.
Chris Monks said: “With the arrival of Mathew Russell, the SJT’s new CEO, this is the right time to step aside and return to my former work as a freelance director, writer and teacher.
“I have several sizeable theatre projects in development which I’m looking forward to realising in the coming months.
“I’ve spent seven years in Scarborough and made some wonderful friends.
“I’ve been very proud of the shows I’ve directed here and the significant progress we’ve made in widening the scope of our productions in a very challenging economic environment.
“I consider the success of our community work through SJT OutReach and the recent opening of the OutReach Rooms to be two of the most significant achievements of my career, and vital in developing the new audiences the SJT needs to ensure a prosperous future.
“There are extremely dedicated and talented people working for the SJT; I wish my staff, our audience and everyone associated with it the best of luck for the future.”
Richard Grunwell, Chairman of the Board of Trustees, said: “Chris has been dedicated in using his considerable talent for the benefit of the Stephen Joseph Theatre; particularly his adaptations in musical theatre, his foresight in developing the SJT OutReach work and the imagination to bring it in-house.
“We thank him and we wish him well in his career ahead, knowing that he leaves a legacy upon which we can build for the future.”
SJT Chief Executive Mathew Russell said: “Although I’ve only known Chris for a short time and have spent little time in his company yet, when I have I’ve been really impressed with his passion for SJT and for using the arts to reach out to the widest range of residents of Scarborough and beyond.
“We will be careful to build on his artistic achievements and in particular his pioneering of SJT’s OutReach work.
“I know everyone involved in SJT, including our audiences and participants, will want to thank him enormously for all his hard work and commitment.
“I’m sorry we won’t have the opportunity to work closely together for long, but look forward to what time we do have, and to ensuring we use it well to help herald the next chapter in SJT’s exciting future.”