In 1990, De Becker achieved a master's degree in law from the KU Leuven. Later that year, she joined the Boerenbond (Flemish farmers’ association) as a lawyer. From 1997-1999, she served as Head of Environmental Consulting at Boerenbond-affiliated accounting firm SBB. In 1999, she became Assistant General Secretary at the Boerenbond, before going on to serve as General Secretary in 2001. In March 2013, she became Vice-President. Finally, on 1 December 2015, De Becker became President of the Boerenbond.

From 2011-2015, De Becker served as a regent on the Council of Regency of the National Bank of Belgium. She also plays an active role as Chairman at SBB Accountants & Advisors. Since 2015, she has acted as Chairman at MRBB, as well as a director at KBC Group, KBC Bank and KBC Insurance. She is also a member of the Group of Ten, while also participating on behalf of the Boerenbond in Flemish social consultation, as well as the Flemish Economic Social Consultation Committee (VESOC).

As of May 2022, De Becker is also Chairman of the Jacob-Ferdinand Mellaerts private foundation, as well as Principal Shareholder of MRBB and Director at ACERTA, where she is also a member of the auditing committee. On 1 September 2022, De Becker was appointed Chairman of both ARVESTA and Aktiefinvest. Since October 2022, De Becker has also served as Director at K&H Bank (Hungary).

At KBC Group, Banking and Insurance, De Becker is also a member of the Appointments Committee, as well as the Risk and Compliance Committee.