The Dalymount Park side’s U21 boss Gino Brazil and Howlett will share the assistant manager role for the coming season.
Howlett, who enjoyed playing spells in the domestic league with Home Farm and Shelbourne, and also cross channel at Coventry and Brighton, commented, "I delighted to be involved in football again. It will be a big change from Monaghan and I am looking forward to it. It is going to be a change for Stephen from having a full-time assistant to having two part-time assistants but we are determined to make it work."
Howlett earned his only international cap in a 1-0 victory over China in the semi-final of the Japan Cup in Sapporo in 1984. Bohemians resume training next Thursday.