Its final phase was not its finest:
He offended too many of the smaller and more particular people he needed to work with, in the Obama administration and abroad. He clashed famously with Afghan President Hamid Karzai, who not entirely without reason thought that Holbrooke wanted him out, as well as with various other personalities in Afghanistan. Pretty soon, it became difficult for the Af-Pak negotiator to spend much productive time in Af-Pak, which wasn't good.
He made an effort to throttle back that magnificent personality -- trying not to give too many interviews, trying not to be a dominating presence. It was a hopeless task, like trying to bottle lightning. If he saw something that offended or appealed to him, Holbrooke could not keep his mouth shut.
The saddest clashes to watch were between Holbrooke and National Security Adviser Jim Jones, another big man. They (and even more, their staffs) traded unkind words in one of those Washington feuds that is talked about constantly but written about too little. The tension grew so large that by early this year, Obama reportedly told his subordinates in the White House that he planned to remove Holbrooke. But the veteran negotiator appealed to his boss, Secretary of State Hillary Clinton, who knew his value, and he was given a reprieve.