Team Chairman Michael Jordan said Silas, who hasn't coached in the NBA since he was fired by the Cleveland Cavaliers near the end of the 2004-05 season, will succeed Brown for now.
Jordan announced earlier in the day that the 70-year-old Hall of Fame coach was stepping down.
"I met with Coach Brown two weeks ago about the team's performance and what we could do to improve it," Jordan said. "We met again this morning after practice. The team has clearly not lived up to either of our expectations, and we both agreed that a change was necessary."
Brown has led the Bobcats since April 29, 2008, compiling a record of 88-104. Charlotte made it into the playoffs for the first time in the 2009-10 season, but got off to a 9-19 start this season.
Jordan said in a letter to the team's fans that he is bent on building a winner.
"I am sure you know that this was a difficult decision," Jordan said. "As I told you back in March, owning this team is my No. 1 priority. I am focused on building a winning team that you can be proud of and I will continue to do whatever is necessary to make that happen."
Brown has a career record of 1,098-904, making him No. 6 among NBA coaches all-time. He won an NBA title with Detroit in 2004 and also took Philadelphia to the NBA Finals in 2001.
He also coached at Denver, New Jersey, San Antonio, the Los Angeles Clippers, Indiana and New York.
He won a 1988 college national championship at Kansas and reached the finals with UCLA.
He is the only head coach in basketball history to win both an NCAA championship and NBA title.