The Phoenix Suns declined Kaminsky's $5.2 million team option last week.
Kaminsky, 27, helps to shore up the Kings' frontcourt rotation, which took a hit with the recent departures of Harry Giles and Alex Len in free agency. Sacramento also agreed to a one-year deal with center Hassan Whiteside.
Kaminsky averaged 9.7 points, 4.5 rebounds and 1.9 assists in 39 games last season, his first with the Suns.
The 7-footer has career averages of 9.8 points, 4.0 rebounds and 1.6 assists in 321 games over five seasons.
The Charlotte Hornets selected him ninth overall in the 2015 draft and he spent his first four seasons with the team.