Emslie took over the running of the whole company last July, after Andrew Flanagan stepped down as chief executive, and was seen as one of the leading candidates to land the role permanently.
However, the role remained unfilled amid shareholder discontent and uncertainty over the future of the company, which received two approaches from UTV.
Eventually a boardroom coup in March resulted in chairman Chris Masters and the rest of the board, apart from Emslie, departing. Richard Findlay took over as chairman and Woodward as chief executive.
Emslie joined Scottish TV's sales department in 1985 and when SMG acquired Grampian TV in the late 1990s he was appointed managing director of its broadcast division to lead the merger. In 1999 he was appointed chief executive of SMG Television and joined the SMG board.
Emslie, who will perform an advisory role to Woodward until the end of April, said he was leaving to pursue other opportunities.
He said: "It has been a huge privilege to have led the television business of SMG and in the last year to act as the chief executive of SMG. I am very proud of what we have achieved over a very challenging time and I am grateful for the support and dedication from all of the staff and the management team."