Baroness Delyth Morgan, the former children’s minister, is to succeed Pamela Goldberg as chief executive of Breast Cancer Campaign on 1 July.
Morgan was chief executive of Breakthrough Breast Cancer for 10 years. She left the charity in 2005, a year after becoming a Labour peer, and became children’s minister in 2008.
Morgan, who has homes in London and Wales, told Third Sector she would relinquish the party whip and become a cross-bench peer now that she was rejoining the voluntary sector.
"Having been a government minister has given me a tremendous perspective on how Whitehall works," she said.
Morgan said she did not think her association with the Labour Party would create problems working with the new coalition government.
"I have always had a good relationship with peers of all parties in the House of Lords," she said.
Goldberg is retiring after 16 years in charge of Breast Cancer Campaign. The organisation has grown from having four staff when Goldberg started to 58 now.