Unsworth was in contention to become the Everton boss after he took charge of the club on an interim basis following the sacking of Ronald Koeman.
But Everton eventually opted to bring in Sam Allardyce, who helped the Toffees to recover from a poor start to the season and finish eighth in the league table in the 2017/18 campaign.
Unsworth returned to his role as the Under-21s boss but he indicated that despite tasting success at that level his heart was no longer in it.
He stressed that he went through a period of self-reflection as he really wanted to be the Everton manager permanently when he was in charge on an interim basis.
The former Toffee admitted that he felt that time was right for him to step up from the Under-21s into senior management.
Unsworth told The Athletic: “It was really tough because I had the [senior] managerial bug.
“It probably led me to a period of reflection about what I wanted.
“But that summer, we brought in a group of players, such as Josh Bowler, Lewis Gibson and Dennis Adeniran and I felt responsible for staying to help develop their careers.
“But I did take not getting the [first-team] job hard.
“I’d done my time with the under-23s and felt it was time to start planning for what came next.”
Unsworth took charge of National League side Oldham Athletic in September as his first job in senior management.
