Leo Strine, chief justice of the Delaware Supreme Court, announced Monday in a letter to the governor that he will retire from leading the state's judiciary this fall.

Strine's decision to retire—which he called “bittersweet” in his letter to Gov. John Carney —appeared to come as a surprise to some Monday, though there had been speculation for weeks in Delaware government and legal circles that he may retire early, according to a Delaware Business Times column published in May.

Strine's early retirement comes about halfway through his 12-year term.

It was unclear Monday why Strine, 55, was choosing to retire now. He has served in the state government, in various roles, for nearly 27 years. He was appointed and confirmed chief justice of the state's highest court in early 2014.

Often referred to as outspoken in news reports and by many in the legal community, Strine also served as the chancellor, or chief judge, of the Court of Chancery from 2011 to 2014. In that role, he led one of—if not the—most important business affairs and corporation law courts in the nation. He also served as vice chancellor of that court from 1998 to 2011.

A 2014 Reuters report on his confirmation as chief justice of the Supreme Court, which hears appeals from the chancery and other state courts, noted that Strine “brings to the high court a national reputation as a workaholic judge who regularly displays his mastery of the state's corporate law through his lengthy opinions.”

In his two-page letter to the governor, which was made public by the Administrative Office of the Courts, Strine said that while his decision to retire was bittersweet, “the main emotion I feel is gratitude” to the people of the state and to many in government for giving him the chance to serve in his numerous roles.

He also said, “I am also grateful, Governor, that I can say to you with confidence that the Judiciary of this state is strong, that we are addressing our challenging and diverse caseloads with diligence, skill and dispatch, and that we are continually looking for ways to serve the people of Delaware even more effectively.”

“In particular, the entire Judiciary is deeply invested in improving access to justice for all Delawareans, and doing what we can to improve the fairness of our criminal justice system,” he continued, before adding that, “as [my wife] Carrie and I move on to a new phase of our lives, I just hope that during my nearly 27 years of service to Delaware, I have contributed in some modest way to making our state stronger and more equitable.”

Carney on Monday said in a statement, “I've known Chief Justice Strine since we worked together in the office of then-Governor Tom Carper, and I've known him to be one of Delaware's top legal minds, and a real public servant on behalf of the people of our state.”

Carney added that “since our time in Governor Carper's office, he has served as chancellor and vice-chancellor on Delaware's Court of Chancery and as chief justice, leading our world-class judiciary, helping to protect Delaware's reputation as the premier venue for business litigation, and working to make our criminal justice system more fair for all Delawareans.”

Strine was on vacation Monday and, according to a representative for the Administrative Office of the Courts, was unavailable for comment.

In recent years, Strine helped push for criminal justice reform in Delaware and wrote important appellate decisions on business issues such as appraisal.

In his letter Monday, Strine made clear that he will be flexible with the exact timing of his stepping down this fall, writing that the move will come ”upon the nomination, confirmation, and swearing in of my successor.”

“To ensure that you and the Senate can hold the special session traditionally called each autumn at your convenience, I am prepared to serve through the end of October, if that is helpful to you,” he wrote.