Maher continued to spend much of the 70s and 80s alternating between theater and the small screen. He appeared in support of Rosemary Harris and Eva Le Gallienne in "The Royal Family" (1975-76) while simultaneously featured on the NBC daytime drama "Another World". Maher earned back-to-back Tony Award nominations in 1979 and 1980 as Best Featured Actor in a Play for "Spokesong", a drama set in Ireland, and "Night and Day", a revival of Tom Stoppard's play. In the 80s, the actor went on to establish himself as one of the foremost contemporary interpreters of the works of Joe Orton (often directed by John Tillinger). As the befuddled but determined police inspector Truscott in "Loot" (1986), Maher all but stole the show and earned a third Tony nomination. He similarly enlivened productions of Orton's "What the Butler Saw" (which he performed in both NYC and London) and "Entertaining Mr. Sloan". One of his last stage appearances was in a 1995 staging of "The Entertainer" at the Long Wharf Theatre.
Maher's stock in Hollywood rose in the 70s beginning with his turn as a Wall Street executive interested in sex games in "For Pete's Sake" (1974) followed by his butler to Warren Beatty in "Heaven Can Wait" (1978). He continued to amass credits in the 80s, although in mostly forgettable fare (e.g., "Going Ape!" 1981, "Funny Farm" 1988). In 1992, Maher played the bishop in "Sister Act" and ushered in a period of intense work. He was a museum curator in "The Shadow" (1994) and a dimwitted colleague of Albert Einstein's in "I.Q." (also 1994). The actor had one of his best roles as the artist's dealer in "Surviving Picasso" (1996) while his last released film "In & Out" (1997) typically cast him as a priest.
In tandem with his feature work, Maher appeared as a regular on a number of TV sitcoms. He was Billy Dee Williams' butler in the short-lived "Double Dare" (CBS, 1985), After a turn as St Peter counseling a returned soul in the Fox comedy "Second Chances" (1987-88), Maher joined the cast of "Anything But Love" (ABC) for the 1989-90 season. More recently, he had a recurring role of a doctor on "Chicago Hope", co-starred as a college chancellor in "Goode Behavior" (UPN, 1996) and was an interior designer on "Style & Substance" (CBS, 1998).