Johnson, who took temporary charge of Middlesex in 2018 after Richard Scott's exit before missing out on the permanent job to Law, saw off competition from figures in the county and international arenas
Middlesex are expected to name Richard Johnson as men's head coach at the end of a long and rigorous recruitment process.
Johnson will move from Surrey, where he has been assistant coach, to take up the role at Lord's.
He replaces Stuart Law, who was dismissed last year after three disappointing seasons.
Richard Johnson is set to join Middlesex as head coach, leaving Surrey
Johnson, who took temporary charge of Middlesex in 2018 after Richard Scott's exit before missing out on the permanent job to Law, saw off competition from figures in the county and international arenas.
The Cricketer understands a longlist for the position was whittled down to a shortlist of four following initial interviews, with Shane Burger, Shane Jurgensen and Alex Gidman also considered alongside Johnson.
Owais Shah and Graham Thorpe were initially included on the longlist.
Johnson has been an assistant coach at Surrey for the past three seasons, but between 2011 and 2018 – a period that included Middlesex's County Championship-winning year – he worked alongside much of the current seam attack.
Johnson was the successful candidate at the end of a long recruitment process
Tim Murtagh, Tom Helm, Toby Roland-Jones and Ethan Bamber were all on the staff at the time and remain involved. Roland-Jones and Steven Finn both played for England during his tenure, while Helm featured in England Lions squads, with whom Johnson also worked on overseas tours.
The terms of the search were extremely deliberate: it was an open process, where candidates had to express their interest and apply, rather than the other way round.
Middlesex didn't approach agents, nor did they begin with a predetermined, preferred contender, hence the lengthy process.