Harlequins have announced that chief executive Mark Evans will leave the Aviva Premiership club at the end of February.
Evans took up his post 10 years ago, and was CEO at the Twickenham Stoop when the club was engulfed by the Bloodgate controversy. But his reign also saw average club attendances climb by 9,000 and the Twickenham Stoop developed into a 15,000-capacity stadium.
Evans, who is to set up a sports consultancy business, said: "It has been a privilege to head up Harlequins for the past decade."
He added: "The development of the stadium, crowd growth, training facilities, the Big Game concept, the club finances and academy has hopefully put the club in an excellent position to be consistently successful at the very highest levels in the next few years.
"With an outstanding director of rugby (Conor O'Shea) in place and the infrastructure sound, I feel it is the right time to move on, much though I will miss the people and enjoyment involved in leading such a great club."
Quins chairman Malcom Wall paid tribute to Evans, adding: "Mark has been an outstanding CEO for Harlequins for the last 10 years. He has led the club from the early, uncertain days of professional rugby and established us as one of the leading lights in the Premiership.
"He has been instrumental in average attendance growth from 3,000 to 12,000 a game, he has driven season tickets sales from 1,000 to 7,000 and has managed the stadium development from a capacity of 8,000 to 15,000.
"He was the architect of the Big Game, which saw 77,000 people attend a Christmas club game last season.
"Under his stewardship, Harlequins have developed a playing academy that has contributed 40% of the current first team squad, the highest proportion in the Premiership. He leaves the club a magnificent legacy in infrastructure and with a team of immense potential.
"We will conduct a comprehensive search to find a replacement. We wish Mark all the very best in his new venture and are delighted to be his first client, as we will use Mark in the short term to continue his valuable work in attendance development."