Williamson joins BAM from rival Cofely UK where she was operations director responsible for £350m worth of contracts.
She transferred to Cofely UK, a GDF SUEZ subsidiary, when it bought Balfour Beatty Workplace three year ago, where she worked as a sector director for nearly seven years.
Williamson said: “I see huge potential to differentiate BAM’s FM business through further innovation in digital asset management and that will come from involving everyone and working collaboratively with BAM’s construction and property development businesses.”
She started her professional career as a civil engineer and led many site projects before starting to specialise in facilities management.
Graham Cash, chief executive of BAM Construct UK, said: “Louise has extensive experience of integrated hard and soft FM services and developing client relationships that will be very valuable in leading BAM FM in its next stage of development.”