In the 1980s, after touring the world mixing live shows, he formed a production collaboration with Chris Hughes. Together they worked with Adam and the Ants, Wang Chung, Ric Ocasek and others. The duo worked together with Curt Smith and Roland Orzabal of Tears for Fears on The Hurting. In an interview with Wyndham Wallace, Orzabal recalled discussions like "a two-against-two battle throughout the album", with Wallace writing that "it all proved worthwhile." Hughes and Cullum used high-tech production techniques on the Paul McCartney song "Motor of Love", according to Mike Evans, giving it a synth sound, with a "lush backing of electronic effects".
He worked with Enya and Nicky Ryan on the album Watermark. James E. Perone notes that Enya's vocals are bathed in reverb leading to a "hazy and impressionistic" sound. Cullum is mentioned by his first name in the lyrics of "Orinoco Flow".
Other artists he has worked with include Tori Amos, Miguel Bosé, Howard Jones, the Human League, the Afro Celt Sound System, Chris Hughes (Shift - a tribute to Steve Reich), Robert Plant, Perry Blake, Mary-Jess Leaverland, Jana Kirschner, Rufus Wainwright, Zucchero, and Phildel.
- 1983, The Hurting by Tears for Fears
- 1988, Watermark by Enya
- 1989, "Motor of Love" from Flowers in the Dirt by Paul McCartney
- 2003, Two Horizons by Moya Brennan
- "Ross Cullum | Credits". AllMusic. Retrieved 16 July 2014.
- Wallace, Wyndham (9 August 2021). "Making Tears For Fears: The Hurting". Classic Pop Magazine. Retrieved 2 September 2023.
- Evans, Mike (2021). Paul McCartney: The Stories Behind the Classic Songs. Welbeck Publishing Group. p. 108-109. ISBN 9781802791563.
- Peron, James E. (2012). The Album. Praeger. ISBN 978-0313379062.
- Bailie, Stuart (8 July 2023). "40 Years of Enya: It's the ruby anniversary of Ireland's most popular solo artist". Belfast Telegraph. Retrieved 2 September 2023 – via ProQuest.
- Quill, Greg (4 March 2004). "Clannad voice goes solo ; Moya Brennan tours new disc Plays Hugh's Room Saturday". Toronto Star – via ProQuest.