Dinwiddie had been with the Indiana Pacers since 2006, serving as the senior vice president of basketball operations from 2017 until present.
As a member of the Sixers' front office, Dinwiddie will work with general manager Elton Brand, who was promoted to that role in 2018.
Dinwiddie is joining a Sixers organization that has reached the playoffs in each of the past three seasons but has also disappointed.
Despite the presence of guard Ben Simmons and center Joel Embiid, the 76ers have been unable to advance past the second round of the playoffs. Last season, they finished a disappointing 43-30 and were swept by the Boston Celtics in the first round.
While Simmons and Embiid are two of the best players in the NBA when healthy, they have both been plagued by injuries during their careers.
Also, Brand and Co. have put a suspect supporting cast around them. Philly lost both Jimmy Butler and J.J. Redick in free agency last offseason while re-signing Tobias Harris and signing Al Horford.
Horford didn't appear to be a good fit alongside Embiid, as he averaged just 11.9 points, 6.8 rebounds and 4.0 assists per game. Harris was also something of a disappointment, though he averaged 19.6 points, 6.9 rebounds and 3.2 assists per contest.
The Sixers' biggest issue was a lack of shooting around Simmons and Embiid. That problem was exacerbated by the fact that Simmons is a poor shooter who has made just two three-point field goals in his three NBA seasons.
One of Dinwiddie's primary goals will likely be to add some capable shooters to the roster via free agency, trade or the draft.
Doing so will be a challenge, though, with Simmons, Embiid, Harris and Horford combining to make over $120 million next season.
Dinwiddie was part of a Pacers front office that pulled off some quality moves during his tenure, including trading Paul George to the Oklahoma City Thunder for a pair of All-Stars in Victor Oladipo and Domantas Sabonis, so perhaps he is the ideal choice to help the Sixers reshape their roster.