Loads of energy!
Harper, born in 1945, made an appearance as Master Bardell in a TV adaptation of
The Pickwick Papers in 1955 and did other child roles, but that wasn't to be his career.
He got a job as floor assistant on
Doctor Who in 1965 and worked his way up to be a director. There he directed
The Caves of Androzani and
Revelation of the Daleks, both considered classics. In 1993, he was slated to direct a 30th anniversary special called "The Dark Dimension", but this was axed before production began.
When it was announced that Harper would return to direct four episodes of series 2,
there was much rejoicing. He directed all four of the Cyberman episodes. He directed three of the following season ("42", "Utopia" and "Last of the Time Lords", the last uncredited) and five of the season after that ("Planet of the Ood", "The Unicorn and the Wasp", "Turn Left" and "The Stolen Earth"/"Journey's End"), as well as the 2009 autumn special "The Waters of Mars". He did the
Whatever Happened to Sarah Jane? two-parter for series 1 of
The Sarah Jane Adventures and the two-parters
The Temptation of Sarah Jane Smith and
Enemy of the Bane for series 2. He has yet to work with
Steven Moffat. (Well, there was "Time Crash", but that was an eight-minute special.)
Harper has also directed episodes of other shows, including
Robin Hood and
The Bill.
The quote is his
Catch Phrase, saying something along those lines before every take.