I am not as well-rounded when it comes to the history of the Court as I would like to be, but I believe Taft was in the upper tier of Chief Justices — not quite on the level of John Marshall, Earl Warren, or Charles Evans Hughes, but above average. Taft was so much better-suited to the Judiciary than the Presidency and it showed in the energy he put into his work on the Court from the time of his appointment up until almost the day that he died in 1930. A seat on the Supreme Court was the job that Taft always wanted (admittedly far more than the Presidency) and he reluctantly turned down three offers by Theodore Roosevelt to appoint him to the Court — the first two times because he felt obligated to finish his mission as Governor-General of the Philippines following the Spanish-American War and the third time because he was Secretary of War and Roosevelt was grooming him to be his successor in the White House.
Taft was extremely happy at the opportunity to finally join the Court when President Harding nominated him in June 1921. Even better was the fact that he was appointed Chief Justice. Taft had a brilliant legal mind and had not only previously served as a Superior Court and Circuit Court Judge at the end of the 19th Century, but had spent two years as the United States Solicitor General (appointed by President Harrison). One of his drawbacks as President was that his speeches and writings tended to be overly legalistic — the work of a judicial mind rather than an executive. He was able to use those skills expertly as Chief Justice, wrote a significant amount of opinions, and was an especially efficient administrator when it came to the Court’s always-busy docket.
One interesting story about Chief Justice Taft came about in 1929 when he was administered the oath of office to new President Herbert Hoover. Taft, of course, had taken that same oath himself exactly 20 years earlier and is the only President who swore in another President (in fact, he administered the oath to two Presidents — Calvin Coolidge in 1925 and Hoover in 1929). However, Taft’s familiarity with the oath was of no help in 1929. Much like Chief Justice John Roberts would do 80 years later when swearing in Barack Obama, Chief Justice Taft flubbed the oath while administering it to Hoover. Then again, perhaps Taft was thinking too much about his own inauguration from 20 years earlier— when then-Chief Justice Melville Fuller administered the oath of office to Taft in 1909, he also botched the oath almost identically to Taft’s mistake with Hoover in 1929.