Slaughter and May is facing a wholesale change of leadership as head of corporate Chris Saul is elected as senior partner.
Saul, who has been head of corporate at the firm for four years and has been a partner since 1986, will take over from Tim Clark at the end of April.
He said: "The critical thing is to keep Slaughter and May as it is, to retain the mix of collegiality and drive."
Saul added: "I want to make sure we have fun. The serious business of the law needs to have its lighter moments. It's about communicating a sense of energy and encouragement."
The election process began two months ago and included soundings taken among the partnership. Partners were informed of the outcome earlier this week. His term as head of corporate, where his clients included Unilever, Huntsman, GE and Goldman Sachs, is understood to have contributed strongly to his successful candidature.
Saul stressed that he would continue to develop the firm's best friends strategy, which was a highlight of Clark's seven-year tenure. "A big part of what Tim has done is the international side and that will be an important part of my role," he said.
Saul's election is the first in a series of management elections at the firm this year. Current practice partner David Frank is retiring this year, leaving his role up for grabs, while a replacement for Saul as head of corporate will also be elected.