Hignett, 45, now heads the firm's planning and environmental unit as a partner.
He previously headed Osborne Clarke's planning unit as an associate.
Hignett says: "The purpose behind the move is to develop my work in the planning and public sector market in a positive environment.
"With the shift of emphasis away from out of town developments, site assembly in town centre locations and public sector work are crucial areas of expertise. This is an expanding area, and Lester Aldridge has a good name for handling it."
He adds "The move from Bristol to Bournemouth may not at first appear to make a lot of sense, but you have to look at the region as a whole.
"I am advising clients in the south and across the nation, not just within the Bournemouth area."