In his 18-year professional career, Dillard spent most of his playing time with the Nashville Sounds Minor League Baseball team.

[1] After his senior year, he was selected by the Milwaukee Brewers in the 15th round (448th overall) of the 2001 Major League Baseball draft.

[2] Having recently undergone left shoulder surgery, his hitting was not as proficient as the Brewers expected,[1] so he instead attended Itawamba Community College (ICC) in Fulton, Mississippi.

[13] He was also selected to participate in the midseason Southern League All-Star Game,[11] in which he pitched a scoreless inning of relief and allowed only one hit.

[7] He made his major league debut that night against the Washington Nationals,[7] pitching one scoreless inning and striking out Aaron Boone.

[8] Dillard played the majority of the 2009 season with the Nashville Sounds, though he did make two relief appearances with Milwaukee in late July.

[11] He began the 2012 season with Milwaukee, but was outrighted to Nashville on July 11 after accumulating a 4.38 ERA with 29 strikeouts over 34 games out of the bullpen.

[11] With a minor league ERA at nearly 10.00, he was reassigned to Double-A Huntsville in late August and elected free agency after the season.

[11] Over eight seasons with the Nashville Sounds (2007–2014), Dillard set the team's career franchise records for wins (39), innings pitched (556+2⁄3), and runs allowed (302).

He bounced back and forth between Helena's roster and pitching for the Triple-A Colorado Springs Sky Sox for the rest of the season in a fill-in role when other pitchers were injured.

[11] He spent the entire 2016, 2017, and 2018 seasons with Colorado Springs, each time becoming a free agent and ultimately re-signing for the next year.

[19] Former Nashville teammate Chris Woodward, who had been hired as the manager of the Texas Rangers in late 2018, encouraged Rangers general manager Jon Daniels to sign Dillard so as to utilize his veteran clubhouse presence in service as a mentor to younger players.

[19] On December 17, 2018, Dillard signed a minor league contract with Texas for 2019,[20] and he was assigned to the Triple-A Nashville Sounds, which had since become part of the Rangers organization.

[8][18] Dillard became a free agent following the 2019 season,[24] but he was later re-signed to a minor league contract with an invitation to spring training.

[11][26] With a lack of affiliated Minor League Baseball in 2020, Dillard, still under contract with Texas, was loaned to the Milwaukee Milkmen of the independent American Association on August 15.

[31] The Nashville Sounds honored Dillard by retiring his uniform number, 17, in a ceremony at First Horizon Park on July 29, 2022.

[32] After retiring from playing in 2021, Dillard was hired to serve as the primary pregame and postgame analyst on Brewers Live telecasts as well as provide color commentary for select games on Bally Sports Wisconsin.