A powerful No.8 with a strong work-rate, Mowen made his Super Rugby debut with the Reds in 2006 before becoming a regular with the Waratahs. In 2012 he opted to leave New South Wales and link up with Jake White at the Brumbies, where he was named skipper. In charge of a young side, Mowen's honest graft proved to be a steadying hand as they improved on a number of poor seasons, narrowly missing the play-offs. During his youth, Mowen captained Australia at Under-21 level, taking charge of a side that included future Wallabies Adam Ashley-Cooper and Cameron Shepherd.