He remained with the club and was appointed interim coach following the sacking of Steve Price part-way through the 2014 NRL season.
He was a powerful runner of the football out wide and provided a great combination with his club teammate, Blues winger Rod Wishart.
McGregor was the foundation captain of the St. George Illawarra joint venture from 1999, leading the team into the 1999 NRL Grand Final against the Melbourne Storm.
[4] He spent time on the sidelines with injury that year and following a shoulder reconstruction he did not play during the entire 2000 NRL season.
In 2017, many predicted St. George Illawarra go finish in the bottom four, due to a disappointing 2016 season, where the club were extremely poor in attack.
In the second half of the 2017 season, St. George Illawarra suffered a terrible drop in form with the club winning only 4 of the last 11 matches.
Due to St. George Illawarra losing the game, North Queensland went on to finish in 8th place and qualify for the finals.
In week one of the finals, the Saints faced Brisbane at Suncorp Stadium with the home side being heavily fancied before the match.
[14][15] On 18 April 2019, McGregor was granted a two-year contract extension by St. George Illawarra, keeping him at the club until the end of the 2021 season.
[20] On November 5 2021, McGregor joined the Parramatta Eels coaching staff as a consultant for the 2022 NRL Season.
[23] Following the conclusion of the 2023 NRL Season, McGregor held talks with the North Queensland Cowboys about the joining the club as an assistant to Head Coach Todd Payten.