His league and championship career at senior level with the Kerry county team spanned ten years from 1974 to 1984.

Kennelly was a regular on the Feale Rangers divisional team over a ten-year period, and won two county senior championship medals.

Kennelly made his debut on the inter-county scene at the age of seventeen when he was picked on the Kerry minor team.

Kennelly subsequently joined the Kerry under-21 team, winning two All-Ireland medals as a substitute in 1973 and on the field of play in 1975.

Over the course of the next ten years, Kennelly won five All-Ireland medals, beginning with a lone triumph in 1975 before a record-equalling four championships in-a-row from 1978 to 1981.

As a young boy, Kennelly showed great skill as a footballer, and his father had influence on his subsequent inter-county career.

Two years later in 1980 Feale Rangers defeated Austin Stacks by three points, thus securing a second county senior championship title.

By the early 1970s, Kennelly had joined the Kerry minor football team; however, he had no success in this grade as Cork dominated the provincial championship.

It was the beginning of a glorious era for Kerry football and Kennelly played a key role in orchestrating much of the success for the team that would come to be regarded as the greatest of all time.

][tone][citation needed] That year he won his first senior Munster title, dethroning Cork as provincial champions in the process.

Reigning champions Dublin provided the opposition and were installed as the favourites over the youngest Kerry team of all time.

[citation needed] Jimmy Keaveney converted a penalty to help Dublin to a 3–8 to 0–10 victory and defeat for Kennelly.

The year began with Kennelly capturing a National League medal on the field of play and a third consecutive Munster title following another win over Cork.

In one of the greatest games of football ever-played 'the Dubs' triumphed and Kennelly was still left waiting for a second All-Ireland medal.

In 1978, Kerry secured a fourth Munster winners' medal in-a-row, however, Kennelly missed the provincial decider.

The Kerry forward lobbed the ball over the head of Paddy Cullen, who was caught off his line arguing with the referee.

[9] In 1979, Kennelly, who was now captain of the side, won a fourth provincial title as Cork fell by ten points in the Munster final.

Mikey Sheehy popped up again to score the decisive goal, as Kerry went on to claim a 1–9 to 1–6 victory in a game that contained sixty-four frees.

In 1981 Kennelly missed Kerry's seventh consecutive Munster title, however, he later lined out in the All-Ireland final against Offaly.

[11] In 1982, Kennelly won his second National League winners' medal before Kerry secured an eighth consecutive Munster final victory over Cork.