Smedley will officially join Williams prior to the Bahrain Grand Prix.
The Middlesbrough-born Smedley's no-nonsense, north east-accented conversations with Massa earned him a cult following among some F1 fans.
The most famous of these was Ferrari's controversial use of team orders - which were banned at the time - at the 2010 German Grand Prix.
Massa was leading from team-mate Fernando Alonso, and Ferrari
wanted to swap their positions
to boost the Spaniard's title chances. Smedley, who has described Massa as "like my little brother", said: "OK. So. Fernando is faster than you. Can you confirm you understood that message."
After Massa had let Alonso past, Smedley came back onto the radio and said: "OK, mate. Good lad. Just stick with him now. Sorry."
The uproar following the incident led to the rescinding of the ban on team orders, on the basis that it was unworkable.
Alonso passes Massa for race lead
At Williams, his role will run in parallel with that of former McLaren and Force India engineer Jakob Andreasen, who joined Williams last month as head of engineering operations.
Broadly, it is Andreasen's role to supply Smedley with the tools he needs for the team to perform at their best, and Smedley's to run the cars at the track.
Both men report to chief technical officer Pat Symonds,
who was recruited last summer
following the sacking of former technical director Mike Coughlan in the midst of the worst season in Williams's history.
The team dominated F1 for large portions of the 1980s and '90s, but have slipped towards the back of the grid in the last few seasons.
Smedley's recruitment is the last of the major changes that Williams believe will lead to a revival and is accompanied by the arrival of Richard Lockwood, who joins from Marussia as head of race strategy.
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