Since Strictly Come Dancing began in the UK in 2004, Goodman has appeared as head judge on the dance competition for BBC One, in all series of the show until the 2016 series. Goodman appeared on the panel with Arlene Phillips, later replaced by Alesha Dixon and then Darcey Bussell, Bruno Tonioli, and Craig Revel Horwood. However, in July 2016, Goodman announced he would be leaving the show at the end of that year’s series. His final appearance was on the Christmas Day Special. On 9 May 2017, it was announced that Shirley Ballas would succeed Goodman as head judge.

In 2005, he voiced Professor in the five-time winning Emmy award children’s program, Auto-B-Good.

Goodman turned professional, won various competitions, and retired from dancing after winning the British Championships at Blackpool in his late twenties. Goodman is a recipient of the Carl Alan Award, in recognition of outstanding contributions to dance and, in 2006 and 2007, a show in which he appeared was nominated for the Emmy Award in the Outstanding Reality/Competition Program category.

In 2006, he appeared on an all singing/dancing version of The Weakest Link and beat Stacey Haynes in the final to win the prize money of £8050 for charity.

Goodman is a West Ham United fan and was featured on the BBC football show Football Focus on 26 September 2009. He is also a keen cricket fan, and, in 2009, took part in a celebrity Ashes cricket game.

Goodman was diagnosed with prostate cancer in March 2009, which was treated surgically at a London hospital.

In October 2011, Goodman appeared on the BBC’s Who Do You Think You Are?, in which he discovered that one of his maternal ancestors was a silk-weaver who died a pauper in the Bethnal Green workhouse. Goodman’s great great grandfather, Josef/Joseph Sosnowski, came from Poland, where he fought in the anti-tsarist November uprising for which he was awarded Virtuti Militari, Poland’s highest military decoration for heroism and courage. After finding out about his ancestry, Goodman said: “I feel no different, I look no different, I am no different and yet I’m not what I thought I was. I thought that I was truly an Anglo-Saxon, English through and through.”

On 30 December 2012, Goodman married his companion of over ten years, Sue Barrett, a 47-year-old dance teacher, in a small ceremony at a London dining club Mosimann’s.

In 2013, Goodman presented the BBC Four programme Len Goodman’s Dance Band Days. He also hosted Len Goodman’s Perfect Christmas on Boxing Day on BBC One.

Between 2013 and 2018, Goodman occasionally presented a Sunday evening music show on BBC Radio 2 during some of Paul O’Grady’s weeks off. Goodman played music that he grew up with, mostly of an easy nature together with spoken memories of his young life and family.

In August 2014, Goodman was one of a number of well known faces taking part in ITV’s two-part documentary series Secrets from the Clink.

In October 2014, Goodman hosted BBC One show Holiday of My Lifetime. The show returned for a second series in February 2016, where he was featured with Dan Walker, Carol Kirkwood, and many more In November 2015, Len and chef Ainsley Harriott presented the BBC show Len and Ainsley’s Big Food Adventure, a 10-part series exploring world cuisine in England and Wales.

In 2017, Goodman presented a family game show called Partners in Rhyme, based on Matt Edmondson’s game, Obama Llama.