[1][2] He has worked in adult and juvenile corrections and as a civil and criminal investigator.

In the Senate, Devlin has served on the Joint Ways and Means Committee and has chaired the Ways and Means Subcommittee on Education and the Subcommittee on Natural Resources.

[2] He served as Senate Majority Leader from 2007 to 2010, succeeding Kate Brown, who successfully ran for Oregon Secretary of State.

[2][6] Devlin was elected for a third term in 2010, defeating Republican Mary Kremer.

[8] On October 23, 2017, Devlin was appointed by Governor Kate Brown to the Northwest Power and Conservation Council, which he accepted and began serving on January 16, 2018.