Clyde & Co partner David Bartlett is leaving the firm to go in-house as vice-president and legal counsel for a FTSE-100 company.
Bartlett, who works in the aviation and finance group, will join GE Capital Aviation Services (GECAS), part of General Electric group (GEC), in January.
He says: "Leaving partnership at one of the leading international law firms was not an easy decision.
"[But] the opportunity to join the market leader and work on deals from the inside is an exciting new challenge. I would not have moved in-house in aviation for anyone else other than GECAS."
Bartlett joined 100-partner Clyde & Co in 1988. He became a salaried partner in 1995 at the age of 29 while working in the firm's Hong Kong office.
His age is one of the reasons he decided to leave private practice: "I made partner at a somewhat young age so thought the time was now right to do this.
"I would certainly not rule out a return to private practice. But for the time being, I am staying with GECAS."
GECAS, which is not a client of Clyde & Co, approached Bartlett earlier this year. He will relocate to Shannon, Ireland.
Senior partner John Dunt says: "It does not surprise me that David was attracted to the commercial in-house role.
"It is always sad to lose a partner but some consolation is that we lose him to a senior position in the aviation industry."
Bartlett is the second lawyer who has joined GEC from private practice this summer. In August, Mayer Brown & Platt's London senior partner Jeff Gordon joined the organisation as head of legal (The Lawyer, 9 August).