In the legislature, Colburn was viewed as a low-profile lawmaker who was a reliable conservative vote as well as an advocate for rural interests. Prior to being elected to the
Maryland State Senate, Colburn was a member of the
Maryland House of Delegates. While serving in the House, he was a member of the Constitutional and Administrative Law Committee from 1983 to 1986, the Environmental Matters Committee from 1987 to 1991, and a member of the Governor's Committee on Employment of the Handicapped from 1984 until 1990. In addition, he was also on the
Lead Poisoning Prevention Commission. While in the Maryland Senate, Colburn served on the Education, Health and Environmental Affairs Committee from 2003 to 2010, the Joint Committee on Administrative, Executive and Legislative Review since 1996, the Joint Committee on the
Chesapeake and Atlantic Coastal Bays Critical Area since 2003, the Executive Nominations Committee since 2008 and the Oyster Advisory Commission. He previously served as Chair of the Alcoholic Beverages subcommittee. He served on the Senate Budget and Taxation Committee, the Public Safety, Transportation and Environment subcommittee and the Capital Budget subcommittee. Colburn previously served on the Judicial Proceedings Committee from 1995 to 2003, and the Special Committee on
Substance Abuse from 2001 until 2003. In 2004, he served on the Senate Special Commission on Medical
Malpractice Liability Insurance and from 2006 until 2006, served on the Agricultural Stewardship Commission. Colburn was the Senate chair of the
Eastern Shore Delegation, a committee he served from 1999 to 2015. He was a member of the Maryland Legislative Sportsmen's Caucus from 2001 to 2015, the Maryland Rural Caucus from 2002 to 2015, the Taxpayers Protection Caucus from 2003 to 2015, and finally the Maryland Veterans Caucus from 2004 to 2015. ==Post-legislative career==