She was picked today (Saturday 20 July) from an all-woman shortlist of two, beating Anne Marie Waters, from London, an outspoken campaigner against Sharia law.
Dr Sen is the director of the African Leadership Programme at the London School of Economics (LSE) and lives in the constituency.
She was previously head of the Human Rights Unit at the Commonwealth Secretariat and has a background in policy, advocacy, campaigning, diplomatic and academic work.
She said in her application statement: “I have not sought selection at any time previously.
“I do so in Brighton because it is my home and I want to represent my community.”
After her selection today she said: “I will fight for people who find it hard to pay their fuel bills, who are in danger of losing jobs, who find their rents are too high, who are turning to payday loan companies – these problems stop people living full lives and taking care of their families.
“People are struggling to make ends meet and those who need support are condemned as scroungers and cheats.”
Like Caroline Lucas, Dr Sen has a PhD and claims strong green credentials.
Labour has now chosen candidates for all three parliamentary seats in Brighton and Hove for the next election which is expected to be held in May 2015.
The three constituencies are among Labour’s top 30 target seats.