Cormier went to Lafayette High School, and graduated in 1998. He attended the University of Alabama, and in his pitching career there, he went 31-16 with a 3.98 ERA and 17 saves. Lance started his career as a closer and recorded a University of Alabama freshman record 11 saves. In 2000, he played collegiate summer baseball with the Wareham Gatemen of the Cape Cod Baseball League. In his junior year, he switched to being a starting pitcher and went 20-8 in the last two seasons of his college career. A highlight of his college career includes being a first team Academic All-American in his senior year. He graduated in 2002 with a degree in finance.
In 2002, Cormier pitched for the Single-A South Bend Silver Hawks and the Yakima Bears. With the Silver Hawks, he went 3-0 with 17 strikeouts and a 2.93 ERA in 27.2 innings. With the Yakima team, he went 0-0 with 3 strikeouts and a 27.00 ERA in 1 inning. His combined statistics for the year were 3 wins and 0 losses, with 20 K's and a 3.83 ERA in 28.2 innings pitched. Cormier played 15 games for the Lancaster JetHawks in, going 6-5 with 59 strikeouts and a 3.82 ERA, before being moved up to the Double-A El Paso Diablos. He had 2 wins and 3 losses, 26 strikeouts, and a 6.10 ERA with the Diablos. His stats for the season were an 8-8 win-loss record, 85 strikeouts, and a 4.53 ERA in 135.2 innings. Lance started with El Paso, going 2-3 with a 2.29 ERA in 10 games, including one of his best games on May 6, where he allowed 2 hits in 7 innings and struck out 10. In May, he was promoted to the Triple-ATucson Sidewinders, where he had 1 win and 1 loss and a 1.77 ERA. On June 18, he was called up to the big leagues when pitcher José Valverde was placed on the disabled list. His first major league start was on June 19 against the Tampa Bay Devil Rays. He lost 11-4, and allowed 5 hits in 1 inning, and was sent back down to Tucson, where he was elected the Diamondbacks June Minor League Pitcher of the Month. After being brought back up to the majors on July 29, Cormier beat the Houston Astros, 6-4 in 6.0 innings pitched. He struck out five, and recorded his first major league hit. He made a move to the bullpen after losing his next 2 games. From August 29 to September 11, batters only hit.136 off of Lance. He recorded his first big-league RBI on July 29. In, Cormier appeared in 67 games for the Diamondbacks. His 7 wins tied for fourth place among National League relief pitchers. He pitched 18.0 scoreless innings at the beginning of the season, and on April 29, he recorded a career-high four strikeouts against the San Diego Padres. He compiled a 1.04 ERA in his last 9 games of the season.
Atlanta Braves
On December 7, 2005, Cormier was traded to the Atlanta Braves along with pitcher Óscar Villarreal for catcherJohnny Estrada. He made his first appearance for the Braves on April 3,. After being demoted to the Richmond Braves on August 21, Cormier was called back up to the big league team four days later on August 25. Cormier suffered an injury during spring training which kept him out for the season's first two months. In his season debut, he allowed 8 earned runs in only 4 innings against the Chicago Cubs. In his next start, he allowed 5 earned runs again against the Cubs. It was obvious that he needed more rehab, and was sent down to Triple-A Richmond. After pitching a complete game shutout in Richmond, Cormier was called up on August 2. He allowed 2 earned runs in relief against the Colorado Rockies on August 3. On August 11, his first start since June 3, Cormier allowed 4 runs in 4 innings and left with a no-decision. He earned his first win of the 2007 season on August 27 allowing 2 runs in 7 innings pitched. He won consecutive starts for the first time in his career one start later against the Philadelphia Phillies. He finished the season a disappointing 2-6 with a 7.09 ERA. Cormier was designated for assignment on November 30,, to make room for Tom Glavine. Consequently, he was released on December 7,.
Baltimore Orioles
On January 21,, he signed a minor league contract with an invitation to spring training with the Baltimore Orioles. He was 3-3 with a 4.02 ERA in 45 games for the Orioles.
On January 16,, he signed with the Tampa Bay Rays. In two seasons with the Rays, he was 7-6 with a 3.55 ERA in 113 games.
Los Angeles Dodgers
On February 16, 2011, he signed a minor league contract with the Los Angeles Dodgers and made the big league club out of spring training. The Dodgers mostly used him in long relief, where he was 0-1 with a 9.88 ERA before he was designated for assignment on May 24. On June 2, he cleared waivers and became a free agent.
Return to Tampa Bay
Cormier signed a minor league contract with the Tampa Bay Rays on June 6, 2011. He was assigned to the Triple-A Durham Bulls. With Durham, he appeared in 20 games and was 4-3 with a 5.51 ERA.
