The 27-year-old is to take charge for the eight remaining Specsavers County Championship games, starting with Monday’s historic day-night game against Gloucestershire.
Sussex say the role will be reviewed at the end of the season.
Brown joined the Sussex junior set-up as an 11-year-old and made his debut ten years ago. Capped in 2014, he was vice-captain last season and stood in when Luke Wright was missing through injury.
Having got the taste for the role and done well, he was the obvious choice when Wright stepped down at the beginning of June. Chris Nash led Sussex to two wins while Brown recovered from a finger injury but Nash returned to the ranks.
Brown said: “It will be a very proud moment for me personally when I lead the team out for the first time as full-time captain on Monday – and a massive honour. I enjoyed doing it last year but I think the squad is different now. It felt like quite a young side before but now we’ve got a much bigger group of senior players with a lot of solid cricketers. The dressing room runs itself in a lot of ways but I know there are guys I can turn to for advice.”
Leading Sussex last season has given Brown valuable insight for what is likely to be his biggest challenge – keeping wicket to the high standards he demands of himself and coping with the demands of captaincy at the same time.
“I learned a lot about that,” he admitted. “When that bowler turns at the top of his mark that’s my trigger to focus on the next ball and being ready to catch it!
“It sounds simple but it is massively important to me that I contribute to the team in terms of keeping consistently well and scoring runs. My form with the gloves and the bat when I did the job last year was pretty good – I don’t want the captaincy affecting that side of my game. It’s a challenge I am looking forward to.”
Successive victories over Worcestershire and Leicestershire revived Sussex’s Division Two promotion challenge while Brown got back to full fitness. “We’ve got some momentum which is important,” added Brown. “If we keep playing good cricket then the table will look after itself.”
All nine of next week’s games in the Specsavers County Championship are day-night affairs starting at 2pm played with a pink Dukes’ ball. Spectators can get into the 1st Central Ground for all four days for just £10 after 4pm.