Career
He has composed musical scores for dozens of television dramas, with over 500 hours of shows played internationally. Some of his best-known scores are for the television shows Lois & Clark: The New Adventures of Superman, Charmed, and Supernatural. Gruska started his career as a singer/songwriter.
He had recording contracts with American Broadcasting Company Records and Warner Brothers
Records with the band MAXUS, for which he was the lead singer and songwriter. Warner Brothers Records later released his solo album Which One of Us Is Maine, which Gruska also produced.
In November 2014, the 200th episode of Supernatural, titled "Fan Fiction", aired on The CW. Gruska wrote and produced two songs for the episode (co-writing the lyrics with screenwriter Robbie Thompson). Within 24 hours after the episode aired, one of the songs, "The Road So Far", was #3 on the iTunes soundtrack chart and #57 among all songs on iTunes.
2014: American Society of Composers, Authors and Publishers Film/television Award - Score, Supernatural Nominations.