The new advice firm has been established as part of a £200m joint venture between LSL and investors Pollen Street Capital.
LSL owns companies in property financial services, surveying and estate agency, including mortgage network Primis, e.surv and Your Move.
The investment in debt and equity will enable Pivotal Growth to acquire other mortgage firms.
Pivotal Growth has entered a long-term arrangement with Primis, and firms acquired in future will be expected to join the network.
LSL has committed up to £33.5m and Pollen Street Capital up to £62.4m to support acquisitions. This will be supplemented by external debt finance in Pivotal Growth, with a view to an exit over three to six years.
LSL and Pollen Street Capital’s investments of £19.1m each will give them a 47.8 per cent equity share of Pivotal Growth.
The additional investment of £14.4m from LSL and £43.3m from Pollen Street Capital will be delivered by way of loan notes.
Embley has won permission from the LSL board to invest £4m into Pivotal Growth for a 4.4 per cent share. He departs as non-executive chairman on 28 April, but will remain on the board as a non-executive director.
Jane Cross, previously chief risk officer of Primis and managing director of E.surv, has been appointed chief operating officer.
David Copland, previously director of mortgage services at LSL, will become strategy and business development director.
LSL chief executive David Stewart, and Ian Gascoigne, partner at Pollen Street Capital, will become directors of Pivotal Growth.
Stewart said: “The launch of Pivotal Growth marks a significant milestone in the implementation of the group’s strategy. It follows other significant steps we have taken to strengthen our management team, and recent acquisitions of Mortgage Gym and Direct Life & Pension Services.
“The Pivotal Growth joint venture with Pollen Street Capital will enable us to establish a leading position in the provision of direct-to-consumer advice and underpins the position of our Primis network.
“I look forward to describing our plans further when we release our preliminary results on 28 April.”
Gascoigne added: “We are highly enthusiastic to support Simon Embley and his team in the launch of Pivotal Growth.
“We believe that Pivotal Growth has potential to quickly become a market leader, while delivering pioneering levels of innovation and the highest standards of customer service in the industry.”