Hill handed in his notice in December, after almost two years with the firm.
Roger Brown, sales and marketing director at Portillion, says: “David has resigned from the company to pursue other career opportunities and we are in the advanced stages of appointing a replacement.”
Portillion is in the middle of applying to the Financial Services Authority for its authorisation to become a mortgage lender.
It plans to launch a range of savings products direct and mortgages through intermediaries.
Mortgage Strategy revealed in June 2011 that it had secured over £58m in investment from SBI Group of Japan and had set an original launch date of January 1 2012.
Brown says although it has missed its January 1 deadline, it is confident it will launch in 2012.
Stephen Knight revealed his plans to launch a lender called Checkmate Mortgages in 2007 which was later rebranded to Portillion in February 2010.
In February 2011 Knight he was forced to step down because of a brain tumour.