He is the head coach at Pershing High School and last played for Chieti of the Serie A2 Basket.

[9] Prior to the beginning of the 2009-10 NCAA Division I men's basketball season, Sims was one of two members (along with Manny Harris) of the 2009–10 Michigan Wolverines men's basketball team named among the 50 preseason Wooden Award watch list nominees.

Born in Detroit, Michigan, as the son of Lolita Pruitt and DeShawn Sims Sr.[2] He claims to have 13 brothers and sisters.

He placed third in the Hal Schram Mr. Basketball of Michigan voting, trailing David Kool and Tom Herzog.

[18][19] His brother, Marcus Pruitt, who was a 6 ft 11 in (2.11 m) junior at Pershing, was fatally shot during Sims's freshman year.

[22] On November 29, 2008, against Savannah State, Sims posted game-highs of 23 points and 12 rebounds, including an overtime buzzer beater as Michigan overcame a 20-point half time deficit.

[23][24] Sims, served as sixth man during November, led the team in scoring with 18 points and tied for the lead in rebounds.

[25][26] On December 3, Sims entered the starting lineup during a game against Maryland in the ACC-Big Ten Challenge.

[27][28][29] On December 6, 2008, Michigan posted its second consecutive win over a top 5 opponent in a rematch against the #4 ranked Duke Blue Devils men's basketball team.

[30] Sims again, led the team in scoring with a career-high 28 points and posted a team-high with 12 rebounds.

[34][35][36] As a result of the major victories and continuing team success they reached the top 25 in the national rankings on December 22 for the first time since February 6, 2006.

[4] On February 26, he was the high scorer again with a career-high 29 points in game against the #16-ranked Purdue Boilermakers men's basketball team that Michigan won 87–78, raising its record to 3–4 against ranked opponents on the season.

[44][45] He was recognized as an All-District second-team selection by the National Association of Basketball Coaches making him eligible for the State Farm Division I All‐America teams.

[48] After going undrafted in the June 24, 2010 NBA draft, Sims signed a free agent contract with the Boston Celtics.

[52] On November 2, he left PAOK, after having played 3 games with the Greek team, in which he averaged 12.3 PPG in 21.7 minutes.

[64] In July 2012, Sims was named to the Phoenix Suns roster for the 2012 Las Vegas Summer League.

[70] He was one of four nonguaranteed training camp invites (along with Damen Bell-Holter, Kammron Taylor and Chris Babb), vying for the final roster spot after accounting for the 14 guaranteed contracts.

[72] After waiving the four players, Celtics president of basketball operations Danny Ainge said all four were welcome to join the team's D-League affiliate, Maine Red Claws, if they were willing to accept the low paying salary instead of higher paying offers overseas.

[78] On July 6, 2017, Sims signed with Italian club Eurobasket Roma, after a monstre season with NPC Rieti.

He planned to employ the 1–3–1 defense and offense and to lean on his former Michigan head coach John Beilein.