The decision was taken to part company with the former Hibs and Sunderland manager after a “horrendous run of results”, culminating in a 9-0 defeat to Celtic in the Premiership on Sunday.
United are now on the lookout for their fifth manager since 2020.
Former Tangerine stars Duncan Ferguson and Michael O’Neill are the early front runners for the post with Liam Fox in interim charge.
Ogren addressed the club’s situation “amid what has been a largely disappointing start to the on-field campaign” with a statement on Tuesday evening.
"A string of poor performances and unacceptable results led to the board making the decision to relieve Jack Ross of his position as head coach,” he said. “Such actions are never taken lightly and, as a board, we took a period of reflection and information gathering after Sunday’s game before coming to our decision.
"This has been a horrendous run of results for the club and for that we apologise unreservedly to our fans. However, it is my belief that the tools and infrastructure remain in place for us to achieve success on the field. This will require everyone to be united behind what we are trying to do.
"In the almost four years of ownership at this club, we have achieved nearly all of our goals and objectives earlier than expected and as a board, we believe we can take things even further soon. I am confident the players, staff, executive team, and board currently in place are the ones to take us forward alongside a new head coach.
"As we begin the process of looking for our new head coach, please know this will take some time and I ask you all to remain patient and supportive.
"Your support has been exceptional, both in terms of ticket sales and vocal backing and I know you simply crave success for our club. I can assure you I share that craving and certainly expect we will again soon be seeing performances in which we can all be proud.”