The 31-year-old had been on the lookout for a new challenge since stepping down from his role with Renegades, last month.
This will be kassad's fourth coaching stint, after previously guiding Wolf, mousesports and Renegades. He spent over a year with the Australian team, whom he led to first-place finishes at two Asia Minors and at the StarLadder i-League Invitational #2.
"I am delighted with the fact that I have the chance to work with Valiance for the remainder of the year," he said in a statement.
"I have been approached by several other organisations, but I have decided to work with Valiance. I genuinely believe in their general plan and vision they have established.
"A huge plus is definitely the fact that I know these players personally. I am looking forward to working with them in order to succeed in accomplishing the goals we have set together."
Aleksandar "kassad" Trifunović (coach)
"Officially part of Valiance&CO for the remainder of the year. I know these players personally and I am looking forward to working with them in order to succeed in accomplishing the goals we have set together." @kassadCSGO pic.twitter.com/1t3xjF1egk— Valiance&CO (@valianceandco) June 13, 2018