He has had a long collaboration with director Hal Hartley, appearing in many of his films, such as Trust (1990), Surviving Desire (1991), Simple Men (1992), Amateur (1994), Flirt (1995), and The Book of Life (1998), starring as Jesus Christ in the latter.

Donovan also played Peter Scottson on Showtime's cable series Weeds.

[1] Donovan played Detective Hap Eckhart in Christopher Nolan's psychological thriller Insomnia (2002) and the Protagonist's CIA handler, Fay, in Nolan's science fiction action thriller film Tenet (2020).

[citation needed] He graduated from Crespi Carmelite High School and attended Pierce College for two years.

He attended American Theater Arts, a combined conservatory and theater company in Los Angeles, where he appeared in the plays Richard's Cork Leg by Brendan Behan and Private Life of the Master Race by Bertold Brecht.