Hennessey joins Sisk from global data centre specialist STACK Infrastructure where he served as construction director EMEA with responsibility for the delivery of its data centre projects across Europe.
He brings nearly 40 years of experience delivering complex projects in Ireland, the UK and Europe.
Owen Sisk, managing director of data centres, said: “We are pleased to welcome John to our team as we look to expand our data centre delivery and meet the needs of our clients across Ireland, UK and Europe.
“John brings a wealth of experience across all geographies in the Data Centre sector and his appointment is timely given that we are seeing substantial growth with a strong pipeline of projects.”