Gajdoš has served in several military functions. Between 1995 and 1998 he worked as the personal secretary of the defence minister and in 1998-1999 he led the protocol department at the Defence Ministry. In 200 he started working at the General Staff of the Armed Forces.
Between the years 2010 and 2013 Gajdoš served as a military representative at NATO’s Military Committee. Since 2013 he has been serving as first deputy of the chief of the General Staff of the Armed Forces.