Although just 42, Addison Mitchell (Mitch) McConnell Jr., the conservative Republican senator-elect from Kentucky, is a meticulous campaigner with a formidable record of public service.

He has been the top elected official of Jefferson County, the state's most populous jurisdiction, since 1977, when he was first elected as county judge/executive.

In winning that office, he became the first Kentucky Republican to gain a county-wide victory in 20 years. The margin was narrow then, and again in 1981. McConnell's election made him the first Republican to win statewide office in the Bluegrass State in 16 years.

A strong advocate of the farmer, McConnell is interested in a seat on the Senate Agriculture Committee, of which his defeated opponent, Sen. Walter D. Huddleston (D), was a member.

McConnell also wants a Judiciary subcommittee assignment, so he can continue working on what has taken on the proportions of a personal crusade: the fight against child abuse.

McConnell became concerned about child abuse when serving as Jefferson County judge/executive. He gained statewide prominence and attracted national interest when he spearheaded an effort to fight child molestation and kidnaping.

The state legislature recently approved a package of laws that have put Kentucky in the forefront of the national effort to combat child abuse.

McConnell, the divorced father of three daughters, earned much of the credit for the success of the legislative initiatives, which provide for such precautions as screening child-care workers.

He served as an aide to former senator Marlow W. Cook and was a deputy asssistant attorney general in the Ford administration before returning to Kentucky to begin his political career.