After attending Selah High School and Yakima Valley Community College, Hull attended the University of Portland. As a senior in 2002, he earned All-West Coast Conference second-team honors for the second straight season after leading the league with eight saves. He posted a 2-3 record in 2002 with a 3.64 ERA and 61 strikeouts in 59.1 innings. 
Hull signed with the Los Angeles Dodgers as an undrafted free agent on June 18, 2002. In his first year Hull pitched in Low A (South Georgia Waves) and then was moved to the Great Falls Dodgers where he won the Pioneer League Championship with 1 win and 2 saves in the final series.Hull pitched for the Vero Beach Dodgers in 2003 and 2004 before being promoted to the Jacksonville Suns during the 2004 season. In 2003, at Vero Beach he went 3-5 with a 2.68 ERA in 31 appearances (14 starts). In 2005 Hull pitched as both a starter and reliever for the Suns and helped them to a Southern League Championship going 2-0 in the playoffs as a starter. Later on Hull won another championship in the 2005 Arizona Fall League for top minor league prospects with the Phoenix Desert Dogs.
He was briefly promoted to the Major League team in May 2007, but was returned to the 51s a few days later without appearing in a single game.
He made his MLB debut on July 24, 2007, against the Houston Astros, working two scoreless innings in relief. On April 7, 2008, he was traded by the Dodgers to the Boston Red Sox for infielder Christian Lara. He was then optioned to the Triple-A Pawtucket Red Sox.
As a free agent in 2009 Hull signed with the Seattle Mariners and played along side Ken Griffey Jr., Ichiro Suzuki, and Felix Hernandez in spring training, before playing out the rest of the season with the Tacoma Rainiers.