The ex-Hull, Derby and Preston boss will take charge of Friday's trip to Bradford but the recently sacked Paul Sturrock will lead the team in the Johnstone's Paint Trophy final
However, Paul Sturrock - who was sacked by the League Two outfit on Sunday - will return to take charge of the Johnstone's Paint Trophy final against Crewe on April 7.
Brown, who has signed a deal until 2015, led Hull City to promotion to the Premier League in 2008 but has been out of management since December 2011.
|PHIL GOOD FACTOR|
|11/4||Southend United are 11/4 with BetVictor to beat Bradford City|
"We've got a few days of training between now and the game against Bradford that will give me a chance to take a look at the players."
The Shrimpers lie six points of the play-off positions with seven games remaining, a gap that Brown aims to close before the end of the season.
"We've got seven league games between now and the end of the season," he continued. "Hopefully we can put a winning run together and give ourselves a chance of reaching the play-offs."