Hackett attended Yale University.
The American Tennis Championships, he stood from 1905 to 1911 seven times in a row ( record ) with his compatriot Fred Alexander in the finals of the doubles competition and could win from 1907 to 1910 together with him this competition. Counter Holcombe Ward and Beals Wright lost in three sets 4:6, 4:6 and 1:6 in 1905 and a year later in four sets 3:6, 6:3, 3:6 and 3:6. In 1907 she beat Nat Thornton and Bryan Grant in three sets 6:2, 6:1 and 6:1. 1908 won Hackett and Alexander against Raymond Little and Beals Wright in three sets 6:1, 7:5 and 6:2. In 1909 she won against George Janes and Maurice McLoughlin in three sets 6:4, 6:4 and 6:0. Your fourth consecutive victory, they celebrated 1910 against Tom Bundy and Trowbridge Hendrick in three sets 6:1, 8:6 and 6:3. At their last finals in 1911 they lost Raymond Little and Gus Touchard in four sets with 5:7, 15:13, 2:6 and 4:6.
Hackett was inducted into the International Tennis Hall of Fame posthumously in 1961.