Timothy Mack was born on September 15, 1972 in Cleveland, Ohio. He attended Saint Ignatius High School in Cleveland. He then attended Malone College and the University of Tennessee where he earned bachelor's and master's degrees. While at Tennessee, he was the 1995 SEC indoor pole vault champion clearing 5.50 meters. In the same year he won the NCAA Indoor title, clearing 5.60 meters. He finished 7th at the NCAA outdoor championships clearing 5.30 meters.
In 2000, Mack competed at the US Olympic Trials, finishing 8th with a vault of 5.53 meters. In 2001, he won the gold medal at the Goodwill Games in Brisbane, Australia, clearing 5.80 meters. Mack won the USA Indoor Track and Field Championships in 2002, clearing 5.70 meters. Later that year, he finished 2nd at the USA Outdoor Track and Field Championships with a vault of 5.74 meters. In 2003, Mack finished 3rd at both the US Indoor and Outdoor Championships, clearing 5.70 meters each time. At the 2004 US Indoor Championships, Mack finished 6th with a vault of 5.60 meters. At the US Olympic Trials later in the year, Mack won the pole vault with a vault of 5.90 meters, earning himself a spot on the US Olympic Team. At the Olympics, he won the gold medal, setting a new Olympic record with a vault of 5.95 meters. He also finished first at the 2nd IAAF World Athletics Final with a vault of 6.01 m, thereby joining the exclusive "6 meters club" of pole vaulters who reached 6 meters. In 2005, Mack tied for 7th at the US Outdoor Championships, clearing 5.40 meters. In 2006, he finished 4th at the US Indoor Championships and 7th at the US Outdoor Championships, clearing 5.50 meters at both meets.