My vote goes to James Dolan. Since inheriting the Knicks and Rangers from his father, he's run both teams into the ground.
NY Rangers
The Rangers saw a decline in performance in the wake of Dolan's increased role in managing the team and failed to make the playoffs from the 1997-1998 season until the 2004–05 NHL lockout, despite leading the league in payroll in most of those years. This was the longest playoff drought in franchise history. Despite fan and media calls for the team's general manager Glen Sather to be fired for the organization's shortcomings, Sather was retained, and even though the Rangers have made the playoffs every year since the lockout ended until 2010 (thanks to the performance of Olympics-Gold-Medalist goal-tender Henrik Lundqvist), they still have yet to become a legit championship contender since their downfall.
NY Knicks
Like the Rangers, the Knicks performed abysmally in the early 2000s, and have yet to recover, mostly thanks to Dolan. Since the 2000-2001 NBA season, the franchise has currently not posted a winning season, nor have they won a playoff game since, and have not made the playoffs since 2004. Dolan has come under fire from many Knicks' fans for the Knicks' run of consecutive losing seasons. Numerous media and informal fan polls, including a recent Sports Illustrated poll have ranked Dolan the worst owner in the NBA. In 2007, NBA Commissioner David Stern criticized Dolan's management of the Knicks, saying "they're not a model of intelligent management." One widely criticized decision was to give shooting guard Allan Houston a 6-year, $100 million maximum contract in 2001, when no other team had offered Houston more than $75 million. Houston retired due to injury after just four seasons and over $40 million remaining on his contract.
In 2003, Dolan hired Isiah Thomas as Team President of Basketball Operations and General Manager to replace embattled executive Scott Layden. Thomas made aggressive moves to re-tool and upgrade the Knicks roster through trades, the NBA Draft, and free agency. Despite the talent Thomas imported, the team underperformed and Thomas was mired in turmoil; Dolan subsequently received the ire of the New York media and Knicks' fans for his commitment to Thomas, who kept on making questionable moves, which never got the Knicks anywhere.
After the 2004-2005 season, the Knicks signed head coach Larry Brown to a 5 year, $50 million contract. After just one (losing) season, Brown was fired and the team bought-out Brown's contract for $18 million. Brown walked away with a total of $28 million for coaching the Knicks for just one year.
After firing Larry Brown, Isiah Thomas assumed duties as head coach of the Knicks. During a staged interview on MSG Network, which has marked the last time Dolan answered questions from any media, Dolan gave Thomas an ultimatum to show "evident progress" or potentially be fired. In the latter half of the 2006-2007 season, with the Knicks within reach of a playoff spot Dolan signed Thomas to a multi-year contract extension. The team subsequently fell out of contention and Dolan has received further criticism for this move. A mere season later, Dolan stripped Thomas of his front office duties, having taken the Knicks to the playoffs just once during his tenure. New team President Donnie Walsh removed Thomas as head coach upon the conclusion of the season.
Other coaches that also had short Knicks tenures include Don Chaney (2001-2003) and Lenny Wilkens (2003-2005). Like Thomas and Brown, they also remained on the Knicks' payroll following their departure from the bench due to their receiving multi-year contracts (and in Chaney's case 2 separate contract extensions).
In 2007, Dolan was named as a defendant in a sexual harassment lawsuit brought forth by a former Knicks executive, Anucha Browne-Sanders. Browne-Sanders accused Dolan of firing her out of spite after she complained about sexual harassment from Isiah Thomas. The court ruled in favor of Brown-Sanders and Dolan had to pay $3 million of the $11 million settlement with MSG being responsible for the remainder of the settlement.
