Junkin was born in North Little Rock, Arkansas, to Kirk, a United Airlines pilot, and Doris, a substitute teacher.

[10] Due to his performance his senior year, Junkin was named to the Second Team College Football All-American.

[18] By the end of training camp, due to struggles learning the outside linebacker position, he made the roster, but lost the starting job to Anthony Griggs.

[19] After the Browns moved to a 4-3 defense for the second game against the Pittsburgh Steelers, Junkin made his debut, and the plan was for him to gradually see more playing time each week.

[23] In his first career start against the Kansas City Chiefs, Junkin had six tackles, including the first one of the game in a 6–3 Browns win.

He returned to the team in early November, but Johnson had played so well in Junkin's absence that he spent the next few weeks as the backup inside linebacker.

He still had faith in Junkin, unlike the Browns, and traded a fifth-round pick to bring him to Kansas City.

[27] Two weeks after the trade, a report came out that Junkin had taken steroids provided by a doctor to treat an injured ankle, and had failed a drug test at the scouting combine as a result.

[28][29] Entering the 1989 season, Junkin competed with Walker Lee Ashley for the second inside linebacker spot alongside Dino Hackett.

[30] Ashley won the job, and Junkin played five games before a shoulder injury sidelined him for the rest of the season.